Department of Physics Colloquia
Department colloquia are intended for a general scientific audience, and researchers from other fields are encouraged to attend.
Where
All colloquia are held in the Optics Building, rooms 234-237. Visitor parking is available in the front of the Optics Building (on the East side).
When
Tuesdays, 2:30-3:30pm. Coffee, tea, and cookies are available from 2:15-2:30pm. Exceptions, such as holidays, will be noted in the schedule.
Current semester's colloquia can be found here.
Special Seminars and MS and PhD Defenses
Special Seminars, as well as MS Thesis and PhD Dissertation Oral Presentations (effective 17 October 2008), will be announced in the semester schedule also.
Giving a Talk
If you are interested in giving a colloquium or special seminar talk, contact the coordinator.
Colloquium and Special Seminar Coordinator
Previous Schedules
- Fall 2010 Schedule
- Spring 2010 Schedule
- Fall 2009 Schedule
- Spring 2009 Schedule
- Fall 2008 Schedule
- Spring 2008 Schedule
- Fall 2007 Schedule
Colloquia, Special Seminars, and PhD and MS Oral Presentations during the Fall 2010 Semester
Optics Building, Rooms 234-237
Tuesdays, 2:30-3:30pm (Unless otherwise specified.)
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August 24 "Ubiquitin" |
August 31 "Does E.T. Exist? Astrobiology and the Search for Life in the Universe" |
September 7 "TBA" |
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September 14 "Hiring Proteins and Viruses for Targeting Cancer Treatment and Controlled Nano-Assembly" |
September 16 PhD Dissertation Presentation: 9:00 AM, NSSTC 2096 |
September 21 "FePt Nanoparticles and Thin Films for Magnetic Information Storage" |
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September 28 "TBA" |
October 5 "TBA" |
October 12 "TBA" |
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October 19 "TBA" |
October 26 "TBA" |
November 2 "TBA" |
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November 9 "TBA" |
November 16 "TBA"TBA |
November 23 "TBA"TBA |
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November 30 No Seminar. Happy Thanksgiving! |
December 7 "TBA" |
Abstract
Ubiquitin
The Boyd lab is interested in understanding the biological function of the small protein, ubiquitin. The discovery of the ubiquitin protein and its involvement in protein degradation lead to the Nobel Prize in 2004. In the Boyd lab the nematode, C. elegans, is being used as a model system for understanding the importance of ubiquitin in a variety of cellular pathways. For example, ubiquitin is known to localize to protein aggregates that form in persons affected by neurodegenerative diseases such as Huntington's Disease. C. elegans strains have been developed that express fluorescently tagged versions the disease causing proteins. Fluorescent microscopy experiments reveal that ubiquitin localizes to these protein aggregates. When ubiquitin is inactivated in worms via RNA interference the protein aggregates still form, but they are significantly smaller than in normal worms. In addition, the lab is using C. elegans strains that express fluorescently labeled ubiquitin in the early embryo. These strains have revealed that ubiquitin is highly concentrated at two populations of transient vesicles in the newly fertilized embryo. Time lapse microscopy of these events will be presented.
Lynn Boyd received a B.A degree from Wake Forest University in 1983. In 1992, she obtained a Ph.D. from the Department of Human Genetics at the University of Utah. Following her Ph.D. research, Dr. Boyd was an American Cancer Society post-doctoral fellow at Cornell University. In January 1998, Dr. Boyd came to the Department of Biological Sciences at UAH as an assistant professor and was later promoted to associate professor with tenure. Research in the Boyd laboratory focuses on the role of the ubiquitin pathway in development and disease. Research papers from the Boyd lab have appeared in journals such as Journal of Cell Science, Genesis, Developmental Cell, BMC Cell Biology and others. One area of the current research is investigating the role of the small protein, ubiquitin, in neurodegenerative diseases such as Huntington's Disease. The lab is using the nematode, C. elegans, as a model system for expression of fluorescently tagged proteins that mimic the disease causing proteins. In addition, the lab is using C. elegans strains that express fluorescently labeled ubiquitin in the early embryo. Preliminary results from these studies will be presented.
Lynn Boyd
UAHuntsville
Abstract
Does E.T. Exist? Astrobiology and the Search for Life in the Universe
I will review the major aspects involved in estimating the number of alien civilizations in the Galaxy
with whom we may communicate.
Biography:
PhD from the Technion - Israel Institute of technology.
Postdoc at Caltech and the University of Utah
Research Assistant Professor at the University of Utah
Assistant Professor at Bates College
Has been Assistant professor at UAHuntsville since 2005
Lior Burko
UAHuntsville
Abstract
Hiring Proteins and Viruses for Targeted Cancer Treatment and Controlled Nano-Assembly
My research group is actively employing viruses, flagella and bacteria to perform varying functions for the development of nanotechnology and nanomedicine. This talk will highlight our recent work in this area and focus on the use of genetically modifiable biomolecules for targeted cancer treatment and controlled nanoparticles assembly. Filamentous phage is a nanorod-like virus (~900 nm long and ~7 nm wide) that specifically infects bacteria and is non-toxic to human beings. It is assembled from a core of DNA surrounded by a shell of coat proteins. The coat proteins are encoded by the DNA, enabling the genetic modification of the surface chemistry of the phage. We first employ the phage display technique to identify phage having breast cancer cell targeting peptides that are fully displayed on the side walls. Two strategies are then adopted to explore the use of cancer targeting phage in targeted cancer treatment. The first is photodynamic therapy where cancer targeting phage is conjugated with a photosensitizer and the conjugate is used to selectively recognize and kill cancer cells through singlet oxygen produced in response to light irradiation. The second is photothermal therapy where cancer targeting phage proteins are assembled around light-absorbing gold nanorods. The modified gold nanorods are used to selectively recognize and thermally destruct cancer cells when exposed to near infrared light. We also employ phage and flagella to assemble inorganic nanoparticles including hydroxylapatite and gold into ordered arrays. Our work shows that genetically modifiable biomacromolecules are unique players in the development of novel nanomaterials and nanomedicines.
Chuanbin Mao is an Edith Kinney Gaylord Presidential Professor of the University of Oklahoma. He received his PhD from Northeastern University in China and postdoctoral training from Tsinghua University in Beijing and the University of Texas at Austin in biomaterials and bionanotechnology. His research interests include biomaterials, biomimetics, bio-nanotechnology and nanomedicine. He has published over 70 refereed articles in international journals. He received CAREER award from the National Science Foundation, New Scientist award from the Oklahoma Center for the Advancement of Science and Technology and Distinguished Junior Faculty award from the Chinese American Chemistry & Chemical Biology Association. He is serving as a senior associate editor for the journal Microscopy Research & Technique. He is on editorial board of the Journal of Tissue Science and Engineering, and Frontiers of Materials Science in China. He is a reviewer of about 20 international journals and serves as proposal review panelists for National Science Foundation and National Institutes of Health.
Chuanbin Mao
University of Oklahoma
Abstract
FePt Nanoparticles and Thin Films for Magnetic Information Storage
High density magnetic recording media requires small, thermally stable magnetic grains. As storage densities increase, the size of these grains must correspondingly decrease. Maximum storage densities are now approaching the 'superparamagnetic limit', in which thermal fluctuations cause the magnetization of the grains to reverse. In order to extend the superparamagnetic limit, new materials must be employed which are more stable than the hcp CoPt type alloys that are currently being used. FePt is the choice material for the next generation of hard drives. In the L10 phase, the magnetic anisotropy energy of FePt is more than 10 times that of hcp CoPt. In order to make use of FePt, techniques must be developed for obtaining uniform isolated grains and schemes must be developed for switching the magnetization of these high anisotropy grains. In this talk I will discuss research done at UA on chemically synthesized nanoparticles, pulse laser annealing, and anisotropy graded media that addresses some of these issues.
Dr. J. W. Harrell, Jr. is professor of physics at The University of Alabama where he has been since 1979. He received his Ph.D. degree in physics from the University of North Carolina in 1969 and was a faculty member at the University of North Dakota from 1969 until 1979. Dr. Harrell's research interests include properties of magnetic recording materials, with an emphasis on magnetic media. He is a research participant in the Center for Materials for Information Technology (MINT) where he has been studying the magnetic properties and phase transformation of chemically synthesized FePt and related magnetic nanoparticles. Other projects in which he is involved include laser annealing of FePt thin films and anisotropy graded media. He has also been involved in modeling and characterizing thermal effects and magnetic interactions in magnetic recording media. Previous work includes the use of NMR to study molecular motion in solids and electron beam curable binders for particulate magnetic media. Dr. Harrell has a strong interest in physics education and has been instrumental in the implementation and development of the Studio Physics approach to teaching introductory physics at UA. He was named an A&S Teaching Fellow for 2000-2003. He served as Chair of the Department of Physics and Astronomy from 1991-98. He is the author of about 100 research papers. Dr. Harrell is also active in the IEEE Magnetics Society. He is a member of the Society's Education Committee, Program Chair of the 2009 IEEE Magnetics Society Summer School, and a member of the Board of Editors of the IEEE Transactions on Magnetics. Dr. Harrell can be reached via email atjharrell@bama.ua.edu or by calling the Department of Physics and Astronomy at (205) 348-3785 or the MINT Center at (205) 348-9404.
J. W. Harrell
University of Alabama at Tuscaloosa
Colloquia, Special Seminars, and PhD and MS Defense Presentations during the Spring 2010 Semester
Department Colloquia: Optics Building, Rooms 234-237, Tuesdays, 2:30-3:30pm.
Other talks as noted.
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January 12 "IBEX: First results, new mysteries, and a possible explanation" |
January 19 "Solar Wind: A Brief Introductory Review" |
January 26 "Cosmic rays: Visitors from the Galaxy"Vladimir Florinski, UAHuntsville Department of Physics [Abstract] |
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February 2 "Turbulence in Fluids - How much do we understand?" |
February 9 "Determining the Timescale and Location of Solar Coronal Heating" |
February 16 UAHuntsville Closed |
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February 23 "Viewing Our Sun from Space and the Sun's Effects on Earth's Environment" |
February 26 MS Thesis Presentation: 2:30 PM, OB 234 |
March 2 "Pickup ions and turbulence in the heliosheath" |
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March 9 "Inflation and the origin of structures" |
March 16 No colloquium. Spring Break. |
March 23 "Frisbees and Boomerangs: When Angular Momentum Meets Aerodynamics" |
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March 30 "Current Topics in Medical Physics" |
April 6 No colloquium. UAHuntsville Honors Day |
April 13 "Computational Plasma Instabilities in Nuclear Fusion"T. J. Chung, UAHuntsville |
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April 20 "First GBM Results on Terrestrial Gamma-Ray Flashes" |
April 27 "The Department's Small Radio Telescope"Laci Gambill, UAHuntsville |
Last colloquium of the Spring semester! Watch for Special Seminars and defenses throughout the summer. |
Abstract
IBEX: First results, new mysteries, and a possible explanation
NASA's Interstellar Boundary Explorer (IBEX) mission was launched in late 2008. The first results of this mission, all-sky maps of neutral atom fluxes, were published in a series of Science papers in October of 2009. The so-called "energetic neutral atoms" (ENAs) measured by IBEX originate from beyond the solar wind termination shock, and their near ballistic trajectories allows ENAs to act as probes of this remote region. While models anticipated certain gross features of the observed flux maps, a number of details were not predicted. In particular, an unexpected bright "ribbon" of ENA flux encircles most of the sky. In this talk I will present background details of the IBEX mission along with modeling predictions. I will conclude by presenting a mechanism that, when incorporated into our 3D models, can quantitatively account for the ribbon.
Jacob Heerikhuisen
UAHuntsville
Abstract
Solar Wind: : A Brief Introductory Review
Solar wind consists of a stream of charged particles - mostly protons and electron - continuously flowing outward from Solar Corona. Solar wind permeates the entire interplanetary space and carries the magnetic field from Sun. Its nature and properties are fascinating and baffling for the Solar Physics community and much of the physical processes behind the observed nature of Solar Wind remain unclear even today. It is often surmised that Solar wing heating is closely connected with the coronal heating. In this presentation we shall briefly introduce some basic phenomena of Solar Wind, including different types of solar winds observed by the spacecraft missions, role of coronal magnetic fields for their origins and summarize the different existing physical models proposed to explain the observations regarding solar wind heating and acceleration.
Brahmananda Dasgupta
UAHuntsville
Abstract
Cosmic rays: Visitors from the Galaxy
Galactic cosmic rays (GCRs) are cosmic energetic particles accelerated to energies far in excess of anything attained on Earth. These ionizing particles can overcome the outward expansion of the solar wind and its magnetic field, and reach our planet, defining near-Earth radiation environment, and possibly affecting Earth's climate. GCR intensities are currently at their record high, owing to unusually quiet solar wind conditions at the end of solar cycle 23 and the start of cycle 24. In this talk I review the basic physics of GCR transport from the very edge of the solar system into its interior. I emphasize the observations by the Voyager 1 and 2 deep space probes measuring GCR intensities in the heliosheath, the external "shield" protecting the solar system from this ionizing radiation. Numerical modeling of cosmic-ray transport using supercomputers is discussed and several examples of matching the models and observations are given.
Vladimir Florinski
UAHuntsville
Abstract
Determining the Timescale and Location of Solar Coronal Heating
The temperature in the core of the Sun is approximately 15 MK while the temperature on the surface of the Sun is about 6000 K. Generally, we would expect the temperature to continue to decrease as the distance from the Sun increased; however in the 1930s, it was discovered that just above the surface of the Sun, the temperature climbs to more than 1 MK in a region of the solar atmosphere called the corona. High temperature emission has also been observed around other Sun-like stars. How energy is transported and released into the corona remains one of the most puzzling unsolved problems in astrophysicists. Determining the timescale and location of the energy release is an important first step in discovering the heating mechanism. In this talk, I will review three popular models for the timescale and energy release in the corona and then discuss the expected observations associated with each model. Finally, I will show data from the most recent NASA missions and compare the observations to the expected observations for each model. I find that there is substantial evidence for two different heating mechanisms in the corona. Furthermore, I find one popular heating mechanism has limited observational support.
Dr. Amy Winebarger graduated with a Ph.D. in Physics from University of Alabama Huntsville in May 2000. She was a research scientist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA and the Naval Research Laboratory in Washington, DC for six years where she specialized in comparing observations of the solar corona with results of numerical simulations. In January 2006, she joined the faculty at Alabama A&M University. She is actively involved in educational outreach and travels to universities and conferences to give lectures on solar and space physics. Her first two Ph.D. students will graduate in May 2010.
Amy Winebarger
Alabama A&M
Abstract
Viewing our Sun from Space and the Sun's Effects on Earth's Environment
In this presentation, we will show the observations of coronal mass ejections (CMEs) from SOHO/LASCO and solar flares from ground based observation made in the Big Bear Solar Observatory operated by New Jersey Institute of Technology. Physical properties of solar atmosphere will also be discussed. Simulation results for CMEs will be shown. Finally, a movie about the solar eruption effects on Earth's environment will be shown.
S. T. Wu
UAHuntsville
Abstract
Pickup ions and turbulence in the heliosheath
With the observations being returned currently by both Voyager 1 and 2 and the IBEX spacecraft, we have an unprecedented once-in-a-lifetime opportunity to investigate the detailed plasma physics of the heliospheric boundary regions. Composed of an inner and outer heliosheath, it is becoming apparent that the physical processes that control the boundary regions of the heliosphere are significantly different from those of the supersonic solar wind. The discovery of the Ribbon by IBEX was a considerable surprise, completely unanticipated by any of the theoretical models. We introduced a mechanism that appears to explain the origin of the ribbon [Heerikhuisen et al., 2010], based on a number of assumptions. We will discuss the physics underlying the ribbon, particularly the detailed pickup process and the evolution of turbulence responsible for scattering pickup ions in the outer heliosheath. We will describe how some of the underlying physics can be incorporated into global 3D MHD-kinetic models. Furthermore, the termination shock has been shown by the Voyager 2 observations to not be a simple MHD shock, with the solar wind plasma experiencing relatively little heating. Thus, the proton distribution function, which is key to understanding the IBEX energetic neutral atom (ENA) observations, is unlikely to be a simple heated Maxwellian, as is typically assumed in global heliospheric models. We will discuss the transmission of protons at the heliospheric termination shock (TS) and describe models of the inner heliosheath proton distribution [Zank et al., 2010]. The effect of these modified inner heliosheath proton distribution on the IBEX ENA observations will be discussed.
G. P. Zank
UAHuntsville
Abstract
Frisbees and Boomerangs: When Angular Momentum Meets Aerodynamics
We review the some fundamental aspects of angular momentum and torque as well as the force and torque acting on an object in a fluid flow. We are then able to understand many of the observed motions of the boomerang and the frisbee when thrown.
Biography:
1938 Born in Los Angeles
1955 BS in physics at Caltech
1964 PhD in physics University of Maryland 1964 in particle experiment
1964-1966 Post Doc University of Wisconsin --- switched to particle theory
1966-2005 Professor of Physics Univ. Wisconsin-Madison
2005--- Semi-retired in Portland OR teaching at Lewis and Clark College. I also have two daughters living here in Portland.
My research primarily concerned the properties and interactions of hadrons (composed of quarks and gluons). Topics studied in my career are: dispersion relations, Regge poles, current algebra, quark models, sigma term, and the QCD string (also known as the relativistic flux tube}. I have published well over a hundred papers on these subjects and I am an APS Fellow in the Division of Particles and Fields.
I also have loved teaching and have co-authored two texts. My teaching was recognized by the Chancellor's award at the University of Wisconsin.
Martin Olsson
Lewis and Clark College
Abstract
Current Topics in Medical Physics
Medical physics, very broadly, is the application of physics principles to the practice of medicine. This is usually divided into the physics of imaging, diagnostic radiological physics, and the physics of the interaction of ionizing radiation with tissue, or therapeutic radiological physics. A general overview of therapeutic radiological physics, especially as practiced at the Clearview Cancer Institute in Huntsville, will be given as well as the newest updates in the field.
Rob Rice received his Ph.D. in physics at the University of Wisconsin-Madison in 1992. Since then, he has been working in radiation therapy in Connecticut, Michigan, and now Alabama. He is currently serving as the Chief Medical Physicist at the Clearview Cancer Institute in Huntsville. CCI is responsible for treating over 150 patients a day on six linear accelerators and is the largest radiation oncology practice in Alabama.
Rob Rice
The Center for Cancer Care
Colloquia, Special Seminars, and PhD and MS Oral Presentations during the Fall 2009 Semester
Optics Building, Rooms 234-237
Tuesdays, 2:30-3:30pm (Unless otherwise specified.)
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August 25 "The Structure of the Outer Heliosphere: Numerical Simulations vs. Spacecraft Observations" |
September 1 "Effects of an Intracavity Resonant Medium on an Optical Cavity" |
September 8 "Sun-Earth Connection: A Tale of Two Ends from a Personal Perspective" |
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September 15 "Electron Kinetics in Gas Discharges" |
September 22 "The Acceleration of Charges Particles at Collisionless Shocks in Space and Astrophysics" |
September 29 "The Legacy of the Ulysses Mission"Steve Suess, NASA MSFC |
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October 6 "Interferometer as an Imaging System" |
October 7 MS Thesis Presentation: 8:30 AM"Using Saturated Absorption Spectroscopy for Detuned Laser Locking" Charles Schambeau, Department of Physics |
October 12 Special Seminar: 2:30 PM"Mathematica in the Classroom" Aaron, Pollock, Wolfram Research |
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October 13 "Termination Shock Surfing" |
October 20 "Simulation of Relativistic Shocks and Associated Radiation from Turbulent MagneticFfields"Ken-Ichi Nichikawa, NASA MSFC [Abstract] |
October 27 "Coherent nanophotoics: How to subdue optics of metallic nanoparticles via semiconuctor quantum dots" |
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November 2 MS Thesis Presentation: 8:30 AM |
November 3 "Heliospheric Calculations with Adaptive Mesh Refinement" |
November 10 "Radio Interferometry and High Frequency Radio Observations of Radio Galaxies" |
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Novermber 17 "Title TBA" |
November 24 "The Interaction of Turbulence with Shock Waves" |
December 1 "Current Models of Solar Coronal Heating" |
Abstract
The Structure of the Outer Heliosphere: Numerical Simulations vs. Spacecraft Observations
The outer heliosphere is the part of the solar wind (SW) which is determined by its interaction with the local interstellar medium (LISM). Since the LISM is partially ionized, charge exchange between atoms and ions plays a major role in the SW-LISM interaction. The topology of this interaction will be described as a function of the SW and LISM properties. The coupling of the interstellar and interplanetary magnetic fields (IMF and ISMF) at the heliospheric interface will be described. The importance of pick-up ions will be emphasized.
Several examples of numerical solution of the SW-LISM interaction problem will be given in the attempt to match them the observations performed by the Voyager 1 (V1) and Voyager 2 (V2) spacecraft. The combined effect of charge exchange and ISMF pressure on the heliospheric asymmetries will be analyzed. Observational constraints on the ISMF orientation will be addressed. I will also show the interaction of the heliospheric discontinuities with the SW perturbations. Special attention will be given to the heliospheric response to Sun's rotation and 11-year period of solar activity.
Finally, I will describe a suite of numerical codes developed by our research group in CSPAR/Physics Department. This suite is capable of performing rather sophisticated, very high-resolution calculations of a variety of problems in space physics.
Nikolai V. Pogorelov
UAHuntsville
Abstract
Effects of an Intracavity Resonant Medium on an Optical Cavity
Optical cavities provide sensitive detection of rotation through the shift in the cavity resonance frequencies, resulting from the Sagnac effect. We investigated the use of the anomalous dispersion, asscioated with an absorption resonance from an intracavity medium, for increasing the frequency separation of the cavity modes. Using a simple Fabry-Perot resonator with an intracavity rubidium vapor cell, we experimentally demonstrated the increase in the cavity scale factor, and found it to be in good agreement with theory for our absorption resonance, with small deviations resulting from the multi-level nature of the Rb87 D2 transition. The widths of the cavity resonances, modified by the presence of the dispersive medium, did not grow as quickly as the scale factor, resulting in increased cavity sensitivity, a finding contrary to previous expectations. We also demonstrated that the ground state hyperfine structure of the Rb87 atom can be used to tune the cavity scale factor via the technique of optical hyperfine pumping.
Krishna Myneni
U.S. Army RDECOM
Abstract
Sun-Earth Connection: A Tale of Two Ends from a Personal Perspective
Our Sun, as a variable star, plays a dominant role in controlling the near-Earth space environment. It is constantly emitting highly ionized material mostly composed of protons and electrons (so-called "solar wind"), carrying solar magnetic field. Thus formed solar atmosphere, called corona, stretches all the way to the Earth and beyond. Its dynamic and magnetic interactions with near-Earth space generate various adverse effects, ranging from spacecraft malfunction in space to power outage on the ground, impacting various aspects of human activities. I will briefly describe such effects related to the emerging research area of space weather. Then I will report my contributions to this area on two topics. One is the extrapolation of the solar coronal magnetic field from magnetic field observations on the solar surface, especially that in a finite active region. The other is the quantitative characterization, from in-situ spacecraft data, of transient structures ejected from the Sun that are often responsible for causing disturbances in near-Earth environment. The effort of seeking physical and causal connections between the Sun and Earth will also be presented. Finally I will summarize and offer some outlook for future endeavors, especially in the context of further collaborations with solar physicists and support by observational facilities, within CSPAR
Qiang Hu
UAHuntsville
Abstract
Electron Kinetics in Gas Discharges
Gas discharges present an example of extremely non-equilibrium systems. This property comes from a large difference between the mass of electrons and the mass of atoms and molecules. Due to the great distinction of mass, the energy exchange in elastic collisions between electrons and gas molecules is inefficient, and the application of electric fields results in electron heating up to energies of a few eV (30,000K) comparable to ionization potential of atoms (with gas remaining at the room temperature). Low temperature plasmas (LTP) of gas discharges are characterized by low ionization degree of 10-6-10-3 and electron temperatures two orders of magnitude larger than gas temperatures. The electrons produce exotic chemical reactions not possible in equilibrium systems. These LTPs are widely used in many modern technologies including semiconductor manufacturing (etching and deposition of computer chips), lighting, plasma display panels, etc. We will present examples of electron kinetics in different plasma sources, describe intriguing physics of self-organization at the kinetic level for ionization waves (striations) in Direct Current discharges, and describe state-of-the-art modeling and simulation of electron kinetics in LTPs.
Dr. Vladimir Kolobov, Manager of Plasma Technologies at CFD Research Corporation, obtained his PhD degree in 1989 from the Leningrad State University in Russia. From 1990 to 1991, he worked as a Senior Research Scientist in the Institute of Hypersonic Velocities and taught at St. Petersburg University in Russia. In 1992-93, he was a Visiting Scientist in the Laboratoire des Discharges dans les Gaz, Universite P.Sabatier, in Toulouse, France. He worked as a Research Associate in the Engineering Research Center for Plasma-Aided Manufacturing at the University of Wisconsin in Madison in 1994-95, and in the Plasma Processing Laboratory at the University of Houston in 1995-97. Dr. Kolobov joined CFDRC in October 1997 and has been responsible for the development of plasma technologies and kinetic methods at CFDRC. He was a key architect of the first commercial software, CFD-PLASMA, for simulations of plasma devices and processes. He was a PI of several multi-year SBIR projects from NSF, DoD, NASA, and numerous industrial R&D projects from GE, Samsung, TEL, Panasonic, MKS Instruments, ABB, Inficon, and other companies. Dr Kolobov is an expert in theoretical and computational plasma physics, physical kinetics, CFD and rarefied gas dynamics, the author of over 50 journal articles and numerous conference presentations.
Vladimir Kolobov
CFDRC
Abstract
The Acceleration of Charged Particles at Collisionless Shocks in Space and Astrophysics
The acceleration of charged particles to the highest energies ever measured (~10**20 eV ) occurs in Astrophysical settings. How this happen is still not fully understood. It is believed by many that the diffusive
shock acceleration mechanisms is the key to this puzzle because it naturally produces a power law for the accelerated charged particle spectrum over a wide range of energies as observations show. However,
radiation measurements from remote astrophysical shocks such as supernovae remnants can take us only so far in figuring out the details of shock acceleration since the radiation is produced by the shock accelerated
particles and we do not see these particles directly. With the discovery of the termination shock around the Sun in the solar system plasma when the Voyager 1 and 2 space craft crossed it in 2004 and 2007, we have
detailed direct measurements of charged particles accelerated by a large-scale collisionless shock and about the shock itself. We will discuss how the Voyager observations challenge us to come up with a more
sophisticated model for charged particle shock acceleration at quasi-perpendicular shocks, which in some ways are not as well understood as at quasi-parallel shocks.
Jakobus A. le Roux
UAHuntsville
Abstract
Interferometer as an Imaging System
The primary function of an interferometer is to produce a set of rays normal to the ideal test surface. This is often aided by the presence of a null lens for aspheric mirrors. However, there is an important secondary function...imaging. In commercial systems there is always a control for imaging the test optic's aperture. In laboratory practice what's usually done is to simply obtain a sharp image of the mirror rim/edge. But we should ask ourselves how well an interferometer performs this imaging function. Are the design criteria between the two functions really compatible? In this presentation we provide an initial look into this question. We will do so in the context of the Fizeau interferometer since this type is currently the main industry workhorse. The test optic employed will be a parabolic mirror and also an off-axis component of that mirror, i.e. an OAP. A null lens will connect the aspheres to the Fizeau. Our chief investigative tool will be optical modeling. The code employed is Zemax.
Joe Geary
UAHuntsville
Abstract
Termination Shock Surfing
Voyager Observations of the heliospheric termination shock (TS) are presented along with a brief discussion of the current and past state of our knowledge of the heliospheric boundary region formed by the interaction of the Sun's solar wind with the local interstellar medium. Voyager 2 observations of the TS are used to construct a model which indicates that shock surfing can account for the 'missing' energy in the solar wind plasma downstream of the TS. (Time permitting) I will discuss our new idea for using the conservation laws for macroscopic conducting fluids (i.e. the conservation laws underlying MHD) to include the back-reaction of the shock surfing mechanism on the electromagnetic fields in a quasi-self-consistent fashion.
Ross Burrows
UAHuntsville
Abstract
Simulation of relativistic shocks and associated radiation from turbulent magnetic fields
Plasma instabilities excited in collisionless shocks are responsible for particle acceleration. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electron–positron jet propagating into an unmagnetized electron–positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electron's transverse deflection behind the shock. The ''jitter'' radiation from deflected electrons in turbulent magnetic fields has different properties than synchrotron radiation, which is calculated in a uniform magnetic field. This jitter radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants. New spectra based on simulations will be presented.
Ken Nishikawa
NASA MSFC
Abstract
Coherent nanophotoics: how to subdue optics of metallic nanoparticles via semiconductor quantum dots
One of the main reasons that currently noble metallic nanoparticles are at the center of significant attentions is the fact that they support surface plasmon resonances. These resonances are now the cornerstones of many applications, ranging from optical nanosensors, sub-wavelength optical waveguides, and nano-thermometers, to fundamental physics such as plasmonic control of emission of semiconductor nanostructures. Despite these, control of the optical properties of metallic nanoparticles is still rather an obscure field of research. This is mostly related to the ultra short relaxation times of plasmons, which make any attempt to control optics of metallic nanoparticles face significant challenges.
In this talk, I will review a novel technique that we have recently developed to optically control plasmons in metallic nanoparticles. This technique allows us to use a semiconductor quantum dot as a tool to make a metallic nanoparticle virtually transparent at the peak of its plasmonic absorption. This control of plasmons here requires interaction of a hybrid system consisting of a metallic nanoparticle and a quantum dot with an infrared laser. I will discuss how this process can be used to optically control heat dissipation rate in metallic nanoparticles, forming what we called "thermal electromagnetically induced transparency".
Seyed Sadeghi
UAHuntsville
Abstract
Radio Interferometry and High Frequency Radio Observations of Radio Galaxies
I will present an overview of the use of interferometric techniques in radio astronomy, the emission mechanisms that produce radio-waves in celestial objects, and a discussion of some of the objects visible in the radio universe. I will then present the results of a multi-frequency investigation of a radio source at the
center of a cluster of galaxies and discuss the implications of these observations for our understanding of physical models of these radio sources.
Nazirah Jetha
UAHuntsville
Abstract
Interaction of turbulence with shock waves
The heliosphere is highly turbulent. The termination shock interacts with the ambient turbulent medium.
I will present some results on solar wind velocity fluctuations, pickup ion driven instability, and modeling the
interaction of turbulence with shock waves.
Xianzhi Ao
UAHuntsville
Colloquia, Special Seminars, and PhD and MS Defense Presentations during the Spring 2009 Semester
Department Colloquia: Optics Building, Rooms 234-237, Tuesdays, 2:30-3:30pm.
Other talks as noted.
|
January 6 No colloquium. |
January 13 "Effect of MeV Si Ion Bomboardment on Thermoelectric Properties of Sequentially Deposited SiO2/AuxSiO2(1-x) Nanolayers" |
January 20 "Statistics in Football and Politics" |
|
January 27 No colloquium today |
January 30 SPECIAL SEMINAR: Talk at 3:45 PM, Refreshments at 3:30 PM |
February 3 "Cosmological Tests Using X-ray Observations of Clusters of Galazies" |
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February 5 SPECIAL SEMINAR: Talk at 2:30 PM, Refreshments at 2:15 PM |
February 10 "Cosmic-ray acceleration and magnetic field amplification at supernova remnant shocks" |
February 17 "Scaling relations in galaxy groups and clusters: defining and breaking" |
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February 24 "Exploration of the Saturn System by the Cassini/Composite Infrared Spectrometer (CIRA)" |
February 25 PhD Dissertation Defense: 10:00 AM, OB 234 |
February 27 MS Thesis Defense: 2:30 PM, OB 234 |
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March 3 "Characterizing the X-ray emitting plasmas in young stars" |
March 10 "RY Scuting Along: Studying a Messy Binary" |
March 11 PhD Dissertation Defense: 10:00 AM, OB 234 |
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March 17 No colloquium. Spring Break. |
March 24 "Fermi GBM Observation of Terrestrial Gamma Flashes" |
March 31 "Infrared Sources for Dynamic Radiometric Sensor Testing" |
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April 3 SPECIAL SEMINAR: Talk at 2:30 PM, Refreshments at 2:15 PM |
April 7 No colloquium. UAHuntsville Honors Day. |
April 14 "Whister Wave Turbulence in Space Plasmas" |
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April 21 "Design and Optimization of Nanostructured Optical Filters" |
May 1 PhD Dissertation Defence: 9:00 AM, OB 234 |
May 6 MS Thesis Define: 9:00 AM, OB 234 |
Abstract
Effect of MeV Si Ion Bombardment on Thermoelectric Properties of Sequentially Deposited SiO2/AuxSiO2(1-x) Nanolayers
We prepared 50 periodic nano-layers of electro-cooling system consisting of SiO2/AuxSiO2(1_x) super lattice with Au layer deposited on both sides as metal contacts. The deposited multilayer films have a periodic structure consisting of alternating layers where each layer is 10 nm thick. The purpose of this research is to tailor the figure of merit of layered structures used as thermoelectric generators. The super lattices were then bombarded by 5 MeV Si ions at three different fluences to form nano-cluster structure. Rutherford backscattering spectrometry (RBS) was used to monitor the film thickness and stoichiometry before and after MeV bombardment. We measured the thermoelectric efficiency of the fabricated device before and after 5 MeV bombardments measuring the cross plane thermal conductivity by third harmonic method, measuring cross plane Seebeck coefficient, and measuring electrical conductivity using Van der Pauw method. As predicted the electronic energy deposited due to ionization by MeV Si beam in its track produces nano-scale structures which disrupt and confine phonon transmission therefore reducing thermal conductivity, increasing electron density of state so as to increase Seebeck coefficient, and electric conductivity, thus increasing figure of merit.
Bio: Dr.Satilmis Budak got his Ph.D. on the Ferromagnetic Resonance studies of some metal oxides thin films like perovskite with CMR and GMR in Turkey. Then, he started to work in the University of Alabama with Dr.Arunava Gupta as a postdoc on 14 January 2004 on building of pulsed laser deposition and chemical vapor deposition systems for magnetic thin films and semiconductor nanowires. He has joined the Center for Irradiation of Materials group in Alabama A&M University to work with Dr.Daryush ILA as a postdoc-research associate on 1 July 2005. Then, he has joined the Department of Electrical Engineering as a faculty in 2007. He is currently working on growth and applications of the nanowires, fabrication of multilayer nano layer films for building of high efficient thermoelectric generator.
S. Boudak
Alabama A&M University
Abstract
Statistics in Football and Politics
The college football season has just wrapped up with the BCS National Championship game, and the new President is about to be inaugurated. We have developed statistical approaches to both of these disparate topics. First, I will discuss the Colley Matrix method for ranking college football teams. This method is used by the BCS as one of the six official computer rankings that help seed the National Championship game. The method is rooted in an old gambling formula due to Laplace and a straight-forward correction for "strength of schedule." I will then turn to a method developed by J. Richard Gott, III, and myself for predicting winners of Presidential elections. Here we apply median statistics state-by-state to form our best guess as to the final electoral returns. In 2004 and 2008, our method called the winner correctly and missed only 1 and 3 states, for a net 4 and 2 electoral votes, respectively.
Wes Colley
UAHuntsville
Abstract
Cosmological Tests Using X-ray Observations of Clusters of Galaxies
X-ray emission from massive clusters of galaxies offers two independent and complementary methods for studying cosmology. The first uses measurements of the ratio of gas to total mass in hot, dynamically relaxed clusters to provide a standard ruler, directly tracing the expansion of the Universe. This procedure produces constraints on dark energy and the mean dark matter density that are competitive with those from type Ia supernova studies. The second method uses measurements of the distribution and growth of cosmic structure observed through the cluster X-ray luminosity function. These studies place tight constraints on the amplitude of the density perturbation power spectrum and provide an independent probe of dark energy. The growth of structure is also potentially a powerful probe of modified gravity theories and inflation. I will review recent results from these experiments and describe the prospects for improvement in the future.
A. Mantz
Stanford University
Abstract
Probing dynamical-dark energy with galaxy clusters
Observational evidence has been accumulated over the past two decades that points toward a "concordance" cosmological model. While this standard model rests on the basis of General Relativity, the large-scale dynamics of the Universe seems to be dominated today by some form of dark energy. Understanding the nature and evolution of this mysterious fluid is among the main quests for contemporary
astrophysics, cosmology and particle physics. One of the most promising ways to reach this purpose is through the study of structure formation in the Universe, that is significantly influenced by dark energy. I will show how the spatial distribution of galaxy clusters, the most massive structures in the Universe, is affected by the presence of dark energy, with especial focus on the possible detection of this effect with future X-ray and Sunyaev-Zel'dovich surveys. I will also show that the abundance of galaxy clusters, probed through the strong gravitational lensing statistics, can validate particular dark energy models.
C. Fedeli
University of Bologna
Abstract
Cosmic-ray acceleration and magnetic field amplification at supernova remnant shocks
I will present the mechanism of particle acceleration at supernova remnant shock waves and the role the production of turbulent magnetic field by cosmic rays has on the process. The topic will be reviewed from the perspective of new observations in X- and gamma-ray bands. I will also show the recent results on the modeling of the magnetic field amplification in the vicinity of shocks with efficient particle acceleration and the implications these results have for the problem of the origin of high-energy cosmic rays.
J. Niemiec
Iowa State
Abstract
Scaling relations in galaxy groups and clusters: defining and breaking
I present results from a number of projects involving both theoretical and observational investigations of galaxy clusters. Firstly, using a sample of galaxy clusters spanning 2 orders of magnitude in mass, extracted from high resolution numerical simulations, I will present baseline expectations for self-similar X-ray M-T scaling relations. These are calculated at a range of density contrasts, derived from both fixed
density contrasts and from contrasts derived from the top-hat model. Secondly, I will present a Chandra and VLA study of a galaxy group which hosts a young restarting radio galaxy, embedded in older emission, where the new source is driving a Mach 2.4 shock into its surroundings and the old source can counteract radiative losses. We demonstrate for the first time that feedback regulated radio galaxies can not only regulate catastrophic cooling in galaxy groups/clusters but also increase the entropy of the ISM, leading to a breaking of the scaling relations.
Nazirah Jetha
CEA Saclay
Abstract
Characterizing the X-ray emitting plasmas in young stars
Young, low-mass stars are copious producers of X-ray emission indicative of magnetic activity in the plasmas of these stars. The trends seen in correlating X-ray parameters with stellar properties in main sequence stars
do not follow for young stars. As a result, different physical mechanisms maybe driving the X-ray emission in young stars. I will present both imaging and spectroscopic data from the Chandra X-ray Observatory of various types of young stars at different evolutionary stages. Our results indicate unique characteristics of the X-ray emitting plasmas of these young stars.
S. Shukla
Vanderbilt University
Abstract
RY Scuting Along: Studying a Messy Binary
A long time ago in a binary far, far away, one star was growing while another was shrinking. Even though this actually happened 6000 years ago, the light from these events in the RY Scuti binary is just getting to us.
Right now we see one star dumping some of its mass onto its companion - active mass transfer and a messy transfer at that. I'll show you how we gleaned information about the two stars (such as masses) and determined that there is a 2000 A.U. double-ring nebula and a 1 A.U. circumbinary disk around the two stars, gas leaking from L2, and an accretion torus around the mass gainer. Eventually, one or both of these stars will go supernova.
Erika Grundstrom
Vanderbilt University
Abstract
Infrared Sources for Dynamic Radiometric Sensor Testing
The presentation will explore some of the challenges and performance issues encountered when using infrared semiconductor lasers and LEDs for dynamic radiometric sensor testing. A hybrid projection system
combining the technologies of an emissive resistor array device and an optically scanned laser diode array projector (LDAP) will be discussed first. It will be shown that high apparent temperature (high radiance)
simulations can most efficiently be produced by the luminescent infrared radiation emitted by semiconductor sources. Aspects of the ideal infrared source will be described along with research to develop new
devices to fill these technology gaps in dynamic infrared sensor testing.
Tommy Cantey
AMRDEC
Abstract
Design and Optimization of Nanostructured Optical Filters
Optical filters encompass a vast array of devices and structures for a wide variety of applications. Generally speaking, an optical filter is some structure that applies a designed amplitude and phase transform to an
incident signal. Different classes of filters have vastly divergent characteristics, and one of the challenges in the optical design process is identifying the ideal filter for a given application and optimizing it to obtain a specific response. In particular, it is highly advantageous to obtain a filter that can be seamlessly integrated into an overall device package without requiring exotic fabrication steps, extremely sensitive alignments, or complicated conversions between optical and electrical signals.
This research explores three classes of nano-scale optical filters in an effort to obtain different types of dispersive response functions. First, dispersive waveguides are designed using a sub-wavelength periodic
structure to transmit a single TE propagating mode with very high second order dispersion. Next, an innovative approach for decoupling waveguide trajectories from Bragg gratings is outlined and used to obtain a uniform second-order dispersion response while minimizing fabrication limitations. Finally, high Q-factor microcavities are coupled into axisymmetric pillar structures that offer extremely high group delay over very narrow transmission bandwidths.
While these three novel filters are quite diverse in their operation and target applications, they offer extremely compact structures given the magnitude of the dispersion or group delay they introduce to an incident
signal. They are also designed and structured as to be formed on an optical wafer scale using standard integrated circuit fabrication techniques.
A number of frequency-domain numerical simulation methods are developed to fully characterize and model each of the different filters. The complete filter response, which includes the dispersion and delay characteristics and optical coupling, is used to evaluate each filter design concept. However, due to the complex nature of the structure geometries and electromagnetic interactions, an iterative optimization approach is required to improve the structure designs and obtain a suitable response.
To this end, a Particle Swarm Optimization algorithm is developed and applied to the simulated filter responses to generate optimal filter designs.
Jeremiah Brown
Grassmere Dynamics
Colloquia during the Fall 2008 Semester
Optics Building, Rooms 234-237
Tuesdays, 2:30-3:30om
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August 9 No colloquium |
August 26 No colloquium |
September 2 "The Dust - Plasma Thruster: A new concept in space propulsion" |
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September 9 "Nonlinear Processes in the Solar Wind Plasma" |
September 16 "Highlights of the Hot Topics in Optics"Lingze Duan, UAHuntsville [Abstract] |
September 23 "Overview of Medical Physics Practice and Research"Rob Rice, Clearview Cancer Center |
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September 30 "Pushing the limits in laser physics: Design of inversionless lasers wtih negative threshold gain" |
October 7 "The Intermittent solar wind: current sheets and their role in energetic particle transport"Gang "Larry" Li, UAHuntsville [Abstract] |
October 14 "Anomalous cosmic ray acceleration and the Voyager paradox"Vladimir Florinski, UAHuntsville [Abstract] |
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October 21 "The Heliospheric Termination Shock" |
October 28 "The Acceleration of Solar Energetic Particles by Coronal Mass Ejection Driven Shocks" |
November 4 "Black body test on the WMAP 5-year data"Ally Zhang, Tsingua University [Abstract] |
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November 11 "Exploring the Extreme Ends of the Gamma-Ray Burst Spectrum" |
November 18 "Global Modeling of Heliospheric Processes: Achievements and Challenges"Nikolai Pogorelov, UAHuntsville [Abstract] |
November 25 No colloquium. Happy Thanksgiving! End of Fall Colloquium series. |
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December 12 MS Thesis Defence: 10:00 AM, OB 234 |
Abstract
The Dust - Plasma Thruster: A new concept in space propulsion
A new scheme of micro propulsion in space i.e. the dust - plasma thruster is proposed. The scheme uses plasma thermal energy to charge externally injected sub micron sized particles and simultaneously create electric fields in the plasma which accelerates them. Particles are subsequently charge stripped and exhausted to produce electrically neutral thrust obviating the need of a charge neutralizer. For reasonable plasma and particle parameters, thrust 10 - 50 micro-N and specific impulse 50 -100 s may be produced. The scheme is shown to have modest power requirements. It may be realized in a simple design where there are no high voltage grids or electrodes, charge neutralizer, valves, pressurized gases etc and can operate in space or vacuum. A layout for the possible configuration is described.
Khare Avinash
CSPAR, UAHuntsville
Abstract
Highlights of the Hot Topics in Optics
Following last semester's special video seminar on nanophotonics, I'm going to play the second part of the documentary DVD, which features two presentations on the recent development on some of the hottest topics in optics. These presentations were given by the topical group chairs of the Optical Society of America in last year's Frontier in Optics Conference. The first presentation reviews a number of new results in the area of quantum electronics, while the second focuses on two recent experiments on human vision and color. This seminar is intended to give students with all background an opportunity to peek into the cutting-edge research in the field of optical sciences. Again, I will give a brief tutorial on some of the subjects covered in the presentations, including attosecond optics, optical cloaking and quantum communications.
Lingze Duan
UAHuntsville
Abstract
The intermittent solar wind: current sheets and their role in energetic particle transport
In past years, measurements of the solar wind plasma have advanced our understanding of MHD turbulence tremendously. At small scales, the solar wind is believed to be very multifractal with nonlinear interactions causing an intermittent energy dissipation, leading to possible current-sheet structures. In this talk, I describe a novel data analysis procedure which allows us to both examine the existence and identify the location of current sheets in the solar wind. The presence of these structures introduces a new source of solar wind turbulence intermittency and can affect the transport of energetic particles.
Previous studies of energetic-particle transport in the solar wind often assume a uniform large-scale background magnetic field, with a turbulent field superposed. With the existence of current sheets in the solar wind, this picture needs to be changed. By constructing a model turbulence of the solar wind that includes explicitly flux-tube-like structures, we show that large scale perpendicular diffusion can come out without introducing a 2D geometry for the underlying MHD turbulence. The implications of this finding is discussed.
Gang "Larry" Li
UAHuntsville
Abstract
Anomalous cosmic ray acceleration and the Voyager paradox
Anomalous cosmic rays (ACRs) are charged particles (ions and electrons) accelerated to high energies in the outer heliosphere, at distances of 80-150 AU from the Sun. The two Voyager deep space probes have been monitoring ACR activity for over 30 years. Starting in 2002 Voyager 1 began to observe a new, lower-energy particle population believed to the related to ACRs. This population became more intense as the spacecraft was approaching the solar-wind termination shock, long though to be the source of ACRs. However, as Voyager 1 crossed the shock near the end of 2004, energetic particle spectra did not unfold into a power law, as was predicted by theories of shock acceleration. Instead, the two-component nature of the spectrum persisted some distance into the heliosheath, the region of shocked solar wind acting as a "buffer zone" between the solar and the interstellar plasmas.
Voyager 2 observations made during its crossing in mid-2007 painted a similar picture, with a few quantitative differences. Several new theories have been put forward to explain the ACR paradox. As an enormous evolving structure with a complex shape and history the termination shock is unlike most interplanetary shocks in that particle acceleration occurs intermittently and only at some locations. For example, acceleration may be more efficient near the ecliptic plane or in the "flanks" of the shocks, both regions not visited by either Voyager. Shock acceleration is also heavily influenced by the dynamics of the solar wind whereby large-scale transient structures disrupt the acceleration process. This talk will discuss competing new theories of ACR acceleration at a blunt and dynamically evolving termination shock in light of the recent Voyager results.
Vladimir Florinski
UAHuntsville
Abstract
The Heliospheric Termination Shock
Observations of the heliospheric termination shock (2007) reveal that the shock is similar in many respects to the structure expected for quasi-perpendicular shocks. However, the dissipation mechanism is fundamentally different and the thermal plasma downstream of the shock is unexpectedly cool. Nonetheless, the basic physics can be understood on the basis a theoretical model developed in 1996 by Zank et al. The observations and simple models will be discussed.
Gary Zank
UAHuntsville
Abstract
The Acceleration of Solar Energetic Particles by Coronal Mass Ejection Driven Shocks
Fast coronal mass ejections (CMEs) in the solar corona drive interplanetary shocks that accelerate solar energetic particles (SEPs) to produce high levels of radiation near Earth that can be hazardous to astronauts and even passengers in high altitude spacecraft, damage satellites, and cause polar lights (aurora). However, the details of the shock acceleration process is currently not well understood. To model this process requires understanding of how energetic charged particles propagate in the largely collisionless solar wind plasma emanating from Sun. These basic propagation mechanisms will be reviewed and it will be showed that they can be combined into a single kinetic transport equation, the so called focused transport equation. This equation has supplanted the standard cosmic-ray transport equation in recent years as the best way to model SEP acceleration at CME shocks. It will be discussed how this equation contains the basic physics of collisionless shock acceleration. Numerical solutions of this equation will be shown to contrast the basic features of the acceleration and transport of SEPs for strong and weak CME shocks which differ substantially from the standard steady-state shock acceleration picture.
Jakobus A. le Roux
UAHuntsville
Abstract
Black body test on the WMAP 5-year data
Pivotal evidence for the Big Bang origin of the cosmic microwave background (CMB) is its black body spectrum. The COBE FIRAS observation constrained any distortion in the all-sky CMB spectrum from the black body shape to 50 parts per million. By means of WMAP 5-year data, here we statistically compared among three well separated frequency passbands ~10,000 angular temperature fluctuations on the one degree scale. We find that on average the frequency dependence of the temperature is about 3 micro-K, or one part per million since T~ 3 K, thereby tightening the COBE constraint on the CMB spectral shape by another 50 times. Unlike COBE also, the residual dT represents the detection of a random component, or non black body signal. Further, a similarly small temporal variation is revealed by comparing spot temperatures at a fixed frequency but in different times. These extra fluctuations may contain important new physics about the early Universe.
B. J. "Ally" Jiang
Tsinghua University
Abstract
Exploring the Extreme Ends of the Gamma-Ray Burst Spectrum
Gamma-ray bursts (GRBs) are extreme phenomena: they are the brightest photon emitting events in the Universe, caused by a collimated ultra-relativistic flow, emerging from the deep potential well of a collapsed object. They are observed across the whole electromagnetic spectrum, spanning almost 16 decades in observing frequency. Multi-wavelength observations of GRBs and their so-called afterglows are used to study the physics of these extreme explosions, their progenitors and their surroundings. In this talk I will focus on the two extreme ends of the GRB spectrum: the prompt high-energy gamma-ray emission, in particular the latest results obtained with the Fermi Gamma-ray Space Telescope (launched in June); and the low-frequency radio emission, which for a small number of GRBs can be observed for years after the initial burst and provides unique information to constrain the physical models.
Alexander van der Horst
NASA MSFC
Abstract
Global Modeling of Heliospheric Processes: Achievements and Challenges
An overview will be presented of magnetic-field-related effects in the solar wind (SW) interaction with the local interstellar medium (LISM), as well as different theoretical approaches for their analysis. The effects to be discussed include heliospheric asymmetries caused by the interstellar magnetic field (ISMF), energy exchange between charged and neutral particles, stability of the heliopause, 11-year cycle of solar activity, the tilt of the heliospheric current sheet caused by the misalignment of the Sun's magnetic-dipole and rotation axes, propagation of large-scale perturbations, the possibility of a strong ISMF, etc. Numerical results are discussed in the context of their relevance to observational data. A package of computer codes capable of analyzing sophisticated flows of partially ionized plasma is described.
Nikolai V. Pogorelov
UAHuntsville
Colloquia during the Spring 2008 Semester
Optics Building, Rooms 234-237
Tuesdays, 2:30-3:30om
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January 8 "GLAST Expectations" |
January 15 "The Multi-Universe Cosmos - A New cosmological theory of the birth of the cosmos, our universe, and its fate"Mr. Karel Velan, Velan Inc. [Abstract] |
January 18 SPECIAL SEMINAR: Talk at 10:30 AM, Refreshments at 10:15 AM, NSSTC room 2096"Chandra/ACIS Observations of Massive Star Forming Regions" Dr. Junfeng Wang, Penn State [Abstract] |
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January 22 No colloquium |
January 29 "Heliophysics Science and the Moon"Dr. James Spann, NASA MSFC [Abstract] |
January 31 SPECIAL SEMINAR: Talk at 2:30 PM, Refreshments at 2:15 PM |
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February 5 "Experimental Studies of Charging of Lunar Dust Levitation, Adhesion, & Transportation" |
February 12 "Quantitative Detection of Protiens Using an Evanescent Based Fiber-Optic Biosensor"Dr. Rakesh Kapoor, The University of Alabama at Birmingham [Abstract] |
February 19 "Relativistic MHD Simulations of Relativistic Jets"Dr. Y. Mizuno, MSFC/NSSTC [Abstract] |
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February 26 "Electric Redshift and Quasars" |
February 28 CONFERENCE: First Annual HEOS Chandra S. Vikram Memorial Lectures |
March 4 "Measuring the Magnetic Field in the Solar Corona"Dr. Steve Spangler, University of Iowa [Abstract] |
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March 11 "Understanding Cometary Atmospheres" |
March 18 No colloquium. Spring Break for students |
March 25 "The FUSE Servey of Diffuse O VI Emission from the Interstellar Medium" |
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April 1 "The Polar Ultaviolet Imager (UVI): A Dozen Years of Auroral Science" |
April 8 No colloquium. UAH Honors Day |
April 15 "Nanophotonics: From Photonic Crystals to Plasmonics"Dr. Lingze Duan, UAH [Abstract] |
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April 22 Ex Luna, Scientia! |
Abstract
Physics and Astrophysics from the Gamma-ray Large Area Space Telescope (GLAST)
GLAST is a major space observatory planned for launch by NASA in May 2008. It will explore the GeV gamma ray region of the cosmic gamma ray spectrum with fifty times the effective sensitivity of previous facilities and help investigate gamma ray bursts. It is expected to make major discoveries involving black holes, neutron stars, cosmic rays and the sun. In addition, it has the capability to detect a signal from annihilating dark matter.
Roger Blandford
Kavli Institute, Stanford University
Abstract
The Multi-Universe Cosmos - A New cosmological theory of the birth of the cosmos, our universe, and its fate
I propose an entirely new approach to the origin of the Cosmos and our universe, one of many in a Multi-Universe Cosmos. The new model eliminates the mysterious singularity at time 0, the origin of which and its explosion no one can explain. It is the first theory which describes the creation of the Universe using laws of physics which hold everywhere and embody the conservation law of energy. Long before any universe was born, the 4-dimensional cosmic space-time was created and all laws of physics established.
Karel Velan
Velan, Inc
Abstract
Chandra/ACIS Observations of Massive Star Forming Regions
Much of the stellar populations inside of the massive star forming regions are poorly studied in the optical and infrared wavelengths because of observational challenges caused by large distance, high extinction, and heavy contamination from unrelated sources. High spatial resolution X-ray images have opened a new window to probe the rich intermediate-mass and low-mass young stellar populations accompanying the massive OB stars in each region. I present Chandra/ACIS observations of two massive star forming complexes, namely the NGC 6357 region and the Rosette Complex, concentrating on the new census of low-mass cluster members and new knowledge of the IMFs. These studies demonstrate the unique power of studying star formation in the X-ray band.
Dr. Junfeng Wang
Penn State
Abstract
Heliophysics Science and the Moon
The Moon is immersed in a plasma environment - the local cosmos - that is "magnetized." It is threaded with magnetic fields that are often "frozen" into the plasma, a state of high electrical conductivity that effectively couples the motions of the plasma and the magnetic field. This inherently strong coupling means that the structure and evolution of magnetic fields (of the Sun, of the Earth, and even of the Moon itself) play an essential role in organizing and regulating the local environment of the Moon - the environment to be experienced by explorers. By working to understand, and so predict, the variations that occur from day to day, and from region to region, the productivity and overall success of future lunar robotic and manned missions can be significantly enhanced. This talk will articulate some of the viable investigations that can be pursued at the Moon that address topics of Solar and Space Physics. The content is based on a community based report in press entitled "Heliophysics Science and the Moon"
Dr. James Spann
NASA MSFC
Abstract
Ultra-High-Energy Cosmic Rays: New Results from the Auger Array
The highest energy cosmic ray particles are the most energetic particles known to us in the universe, and their observations have led us to build one of the largest detector system in the world, the Auger air-shower array. We have detected particles of an energy up to 3x10^20 eV, which is a macroscopic energy. There have been two predictions: one that due to interaction with the microwave background the spectrum should show a turnoff near 5x10^19 eV; this has been confirmed by two experiments, HiRes and Auger. Second, that radio galaxies should be the accelerators, based on the non-thermal optical spectra of knots and hot spots in radio galaxies; this is now tentatively confirmed by Auger. Apart from differentiating various remaining options how to generate these particles, there is one major difficulty: the lack of understanding of the cosmological web of magnetic fields, which may influence the propagation of high energy particles; here it is especially important to understand the role of a galactic wind and its magnetic structure. In analogy to the scattering of particles in the Solar wind I propose, that this scattering leads to a steep distribution function of scattering angles of the deviation from a straight line path for the arriving particles. I will discuss the observational and theoretical limits for an exemplary set of models, the predictions, that result from these models, and how present and future observations will test our conclusions, especially with the Telecope Array (TA), the Auger Array, the neutrino observatory IceCube, and the future space observatory EUSO. There are a number of exciting consequences for high energy physics.
Dr. Peter Biermann
Max Planck Institute (Bonn)
Abstract
Experimental Studies of Charging of Lunar Dust: Levitation, Adhesion, & Transportation
It is well known since the Apollo missions that the lunar surface is covered with a thick layer of micron size dust grains with unusually high adhesive characteristics. The dust grains levitated and transported on the lunar surface are believed to have a hazardous impact on the robotic and human missions to the Moon. A horizon glow and transient dust clouds over the lunar horizon were observed by during the Apollo 17 mission. The observed dust phenomena are attributed to the lunar dust being charged positively during the day by UV photoelectric emissions, and negatively during the night by the solar wind electrons. The dust grains are believed to be levitated by the induced electric fields and transported in the near vacuum environment. The current dust charging and the levitation models, however, do not fully explain the observed phenomena, with the uncertainty of dust charging processes and the equilibrium potentials of the individual dust grains. Since the abundance of dust on the Moon's surface with its observed adhesive characteristics has the potential of severe impact on human habitat and operations and lifetime of a variety of equipment, it is necessary to investigate the charging properties and the lunar dust phenomena in order to develop appropriate mitigating strategies.
It is well recognized that the charging properties of individual dust grains are substantially different from those determined from measurements made on bulk materials that are currently available. An experimental facility has been developed in the Dusty Plasma Laboratory at NASA Marshall Space Flight Center for investigating the charging and optical properties of individual micron/sub-micron size dust grains by levitating them in an electrodynamic balance in simulated space environments. I will discuss our recent results on laboratory measurements on charging of Apollo 11 and 17 individual lunar dust grains by low energy electron beams and by photoelectric emissions. The measurements are made by levitating dust grains of 0.2 to 10 mm diameters, in an electrodynamic balance and exposing them to mono-energetic electron beams and UV radiation. The charging rates and the equilibrium potentials produced by UV radiation and by electron impact are discussed. Photoelectric emission induced by the solar UV radiation is recognized to be the dominant process for charging of the lunar dust. In a unique laboratory facility at MSFC/NSSTC, the optical and physical properties of individual lunar dust grains are being investigated with the objective to better understand the complex lunar dust phenomena in order to develop and evaluate various mitigating strategies. We will discuss the first laboratory measurements of the photoelectric yields of individual sub-micron/micron size dust grains selected from sample returns of Apollo 17, and Luna 24 missions, as well as similar size dust grains from the JSC-1 simulants. The measured yields of micron-size individual dust grains are determined to be more than an order of magnitude larger than the bulk values reported in the literature, with a size dependence that indicates higher values for larger grains. The current and future experimental and analytical programs for investigations of the lunar dust phenomena will be discussed.
Dr. Mian Abbas
NASA MSFC
Abstract
Quantitative Detection of Proteins Using an Evanescent Based Fiber-Optic Biosensor
In recent years, there is a considerable increase in the research efforts in the field of fiber-optic biosensors. Because of their potential sensitivity, detection speed and adaptability to a wide variety of assay conditions, their use as a probe or as a sensing element is increasing in clinical, pharmaceutical, industrial and military applications. I will talk about design aspects of a fiber-optic probe and converting it into a highly sensitive and specific tool for rapid and cost-effective detection and quantification of proteins in serum/plasma samples.
Dr. R. Kapoor
UAB
Abstract
Relativistic MHD Simulations of Relativistic Jets
Relativistic jets have been observed or postulated in various astrophysical sources, including active galactic nuclei (AGNs), microquasars in the galaxy and gamma-ray bursts (GRBs). There are four major problems related to the relativistic jets: 1. formation mechanism, 2. acceleration mechanism, 3. collimation mechanism, and 4. long-term stability. The most promising mechanisms for producing and accelerating relativistic jets, and maintaining collimated structure of relativistic jets involve magnetohydrodynamical processes.
We perform 2D general relativistic MHD simulations involving a geometrically thin accretion disk near both non-rotating and rotating black holes by using newly-developed 3D GRMHD code ''RAISHIN''. In the rotating black hole case an inner jet forms near the black hole region in the magnetic field strongly twisted by frame-dragging. This inner jet/spine lies within an outer jet/sheath produced by the magnetic fields anchored accretion disk. When the jet propagates, such a jet/spine and sheath/wind configuration considerably modifies the stability properties and potential structure of the jet resulting from spine-sheath interaction. We have performed 3D relativistic MHD simulations to study the Kelvin-Helmholtz (KH) instability of magnetized spine-sheath relativistic jets. We found that the growth of the KH instability is reduced significantly by a mildly relativistic sheath flow and can be stabilized by a magnetized sheath flow.
Dr. Y. Mizuno
MSFC/NSSTC
Abstract
Electric Redshift and Quasars
Recently, a new redshift mechanism called electric redshift is developed by Zhang (ApJL 636, 61, 2006), in accord with the five-dimensional fully covariant Kaluza-Klein (K-K) theory with a scalar field, which unifies the four-dimensional Einsteinian general theory of relativity and the Maxwellian electromagnetic theory. The result indicated that a dense, massive, and charged object can significantly shift the light that is emitted from the object toward the red as compared with the Einsteinian gravitational redshift. A compact, electrically charged object with density and mass comparable to those of a neutron star can impart a redshift as great as quasars have. This seminar introduces this new redshift mechanism and discusses the detectability of the electric redshift and the scalar field interaction with possible experiments.
Dr. T. X. Zhang
Alabama A&M University
Abstract
Measuring the Magnetic Field in the Solar Corona
The corona is the outermost layer of the Sun's atmosphere. Remarkably, it has a temperature of 1-2 million degrees Kelvin, while the layers of gases in the photosphere only a few thousand kilometers below (which we see as the disk of the Sun) have a temperature of about 6000 K. The structure of the corona is partly determined by a magnetic field, as may be seen in pictures of solar eclipses. This magnetic field is widely believed to play a role in the heating of the corona, either directly via Joule heating or indirectly via the damping of waves and turbulence which involve the magnetic field. Assessing this role requires measurements of the strength and structure of the coronal magnetic field. I will describe ways in which such information can be obtained by radioastronomical measurements. The physical effect at the basis of these measurements is Faraday Rotation, consisting of a rotation of the plane of polarization of a radio wave when it propagates through an ionized gas with a magnetic field.
Dr. Steven R. Spangler
University of Iowa
Abstract
Understanding Cometary Atmospheres
Understanding the chemical and physical properties of cometary atmospheres is crucial to understanding comets as a whole. However, many properties of cometary atmospheres are still not understood. This is further compounded by the lack of models incorporating information gathered from comet flyby missions. I will discuss my recent and ongoing work to examine the potential impact of gas dynamics, photochemistry, and chemical reactions on the chemical profiles of cometary atmospheres, including an attempt to model chemical profiles in the atmosphere surrounding a non-spherical nucleus. The results have implications for measuring chemical abundances in comets, and in turn, measuring chemical abundances in the outer Solar System and placing constraints on scenarios of Solar System formation.
Dr. Donna Pierce
Mississippi State University
Abstract
The FUSE Survey of Diffuse O VI Emission from the Interstellar Medium
Emission via the O VI doublet at 1031.93 and 1037.62 A is the primary cooling mechanism for interstellar gas at temperatures between 10^5 and 10^6 K. As such, it traces regions where hot gas cools quiescently, interface regions where hot and cool gas meet and mingle, and high-velocity shocks. Over its eight-year mission, the Far Ultraviolet Spectroscopic Explorer (FUSE) was used to observe O VI in both emission and absorption. In this talk, I will present a brief history of the hot component of the interstellar medium (ISM) and the various physical processes responsible for its creation, evolution, and morphology. I will review the results of recent O VI absorption- line studies of the Galactic disk and halo. Finally, I will present the latest results from our survey of diffuse O VI emission from the ISM.
Our observations reveal the large-scale structure of the O VI-emitting gas in the quadrant of the sky centered on the Magellanic Clouds. Its most prominent feature is a layer of low-velocity emission that extends more than 70 degrees from the Galactic plane. By combining absorption and emission measurements along the same lines of sight, we can estimate the emission measure and therefore the density of the emitting gas. We identify two distinct populations of emitting clouds: At low latitudes (|b| < 30 deg), we probe narrow, high-density conductive interfaces in the local ISM. At high latitudes, the low densities and long path lengths are consistent with a location in the Galactic thick disk/halo. Three of our sight lines exhibit O VI emission at velocities consistent with Magellanic H I, suggesting that hot and cool gas is mixing in the interface region of the Magellanic System.
Dr. Van Dixon
Johns Hopkins University
Abstract
The Polar Ultraviolet Imager (UVI): A Dozen Years of Auroral Science
The Polar satellite, originally scheduled for a two-year mission, recently celebrated its twelve-year anniversary of operations. The Ultraviolet Imager (UVI), one of three imagers on Polar, is a camera designed to view Earth's aurora in ultraviolet wavelengths. That remarkable mission is now drawing to a close and the Polar satellite is scheduled to be shut down by the end of the month. This presentation is intended to be a celebration of the UVI investigation and, more importantly, a tribute to the UAH-MSFC collaboration that designed, built, tested and operated the instrument. UVI images allow scientists to monitor the location and behavior of the aurora, determine auroral energies and properties of Earth's upper atmosphere. Advantages of space-based imaging of the aurora and imaging of the upper atmosphere in general will be discussed. Results will be presented from UVI and form other global imagers before and after the Polar era.
Dr. Glynn Germany
UAH CSPAR
Abstract
Nanophotonics: From Photonic Crystals to Plasmonics
In this special seminar, I'm going to play a documentary DVD, which shows a plenary presentation given by Professor Eli Yablonovitch of UC Berkeley at the Frontiers in Optics Conference last September. Dr. Yablonovitch is widely regarded as the father of photonic crystals. In this beautifully organized talk, he took the audience on a tour of structures far smaller than the wavelength of light and reviewed the latest progress in three of today's hottest areas in optics: photonic crystals, silicon photonics and plasmonics. When the size of integrated circuits dropped below the critical dimension for a photonic crystal, which is about 100 nm, electronics and optics have become one thing. With the breakthrough of silicon lasers, a full toolkit for integrated optoeletronics is at hand. Finally, the emerging field of plasmonics will eventually make possible integrated optical circuits.
To help students with limited optics background better understand the talk, I'm going to give a brief tutorial of some of the background knowledge before the presentation. This will be a good opportunity for students to get a taste of conference and learn about the latest development in the field from a world-class expert.
Dr. Lingze Duan
UAH Physics
Abstract
Ex Luna, Scientia!
The Lunar Occultation Observer (LOCO) is a new mission concept being developed to probe the nuclear astrophysics regime.By combining the development heritage of planetary orbital-geochemistry investigations with new developments in astrophysical imaging, a high-sensitivity, scaleable, and cost effective mission is feasible. LOCO will perform an all-sky survey of the Cosmos and study a wide range of astrophysical phenomena including, but not limited to, Galactic nucleosynthesis, supernovae & novae, potential dark matter annihilation processes, active galactic nuclei, and compact objects. I will describe the motivating science, the mission concept, as well as ongoing research and development.
Dr. Richard Miller
UAH
Colloquia during the Fall 2007 Semester
Optics Building, Rooms 234-237
Tuesdays, 2:30-3:30om
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September 4 "Georgia State's CHARA Array - The World's Highest Resolution Infrared Telescope" |
September 11 "Cryogenic Optical Testing of the Primary Mirror Segment Assemblies for the James Webb Space Telescope" |
September 18 "Interferometric UV lithography: from optical fibers to biomembranes" |
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September 25 "Optical Nose: A Novel Mid-Infrared Laser System for Analyzing Gaseous Samples" |
October 2 SPECIAL TIME: Talk at 3:30 PM, Refreshments at 3:15 PM |
October 9 No colloquium. Fall Break week. |
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October 16 "Harnessing the Eclipse: Transiting Planets and KELT" |
October 23 "Quantum Optics: From Basics to Daily Life Applications" |
October 30 "Aurora on Ganymede" |
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November 6 CANCELLED |
November 7 SPECIAL SEMINAR: Talk at 2:30 PM, Refreshments at 2:15 PM |
November 13 "Observe Matter Falling into a Black Hole" |
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November 20 No colloquium. Happy Thanksgiving! |
November 27 "Tornadoes: knowns, unknowns and future directions" |
Abstract
Georgia State's CHARA Array - The World's Highest Resolution Infrared Telescope
Astronomers from Georgia State University's Center for High Angular Resolution Astronomy (CHARA) have designed and built a six-element optical/infrared telescope array on Mt. Wilson in southern California. With its longest baselines of 330 meters, the CHARA Array is capable of sub-milliarcsecond resolution of a variety of astronomical objects. This presentation will include a technical overview of the Array and examples of the science accomplished since the facility became routinely operational in 2005. These results include the detection and imaging of rotationally induced oblateness in rapidly rotating stars, measuring the angular pulsation of Cepheid variable stars, and obtaining the first direct measurement of the diameter of an exoplanet.
Dr. Harold A. McAlister, Georgia State University
Regents' Professor of Astronomy
Director, Center for High Angular Resolution Astronomy
Abstract
Cryogenic Optical Testing of the Primary Mirror Segment Assemblies for the James Webb Space Telescope
Dr. James Hadaway is a Senior Research Scientist in the Center for Applied Optics at the University of Alabama in Huntsville. He has over 20 years of experience in the optical design, fabrication, and testing of high-performance optical systems. He is currently leading the preparations for the cryogenic optical testing of the primary mirror segments for the James Webb Space Telescope, which will take place at Marshall Space Flight Center's X-Ray Calibration Facility.
Dr. James Hadaway
Senior Research Scientist, Center for Applied Optics, University of Alabama in Huntsville
Abstract
Interferometric UV lithography: from optical fibers to biomembranes
Interferometric Lithography is used to produce sub-micron scale periodic structures in glass optical fibers as well as biomembranes and other substrates of biological interest. Normal as well as slanted Bragg-gratings fabricated by this technique within the core of optical fibers are fabricated and used for health monitoring/distributed sensing in carbon-polymer composite structures. Interferometric UV lithography is also used to produce microarrays on phospholipids bilayer membranes as well as other polymer substrates. Phospholipids are one of the major constituents of biological cell membranes and lipidic films have found extensive uses as simple models of cell membranes. Model biomembranes are known to be excellent platforms for biosensing.
The experiments described here were motivated by the promise of interferometric techniques to extend membrane photolithography to produce nanometer scale features. Holographic gratings and microarrays are recorded in azo-dye (NBD)-labeled phospholipid thin films using 244 nm UV light. Diffraction efficiency of these gratings shows extreme sensitivity to humidity and can increase reversibly by two orders of magnitude in air, which is saturated with water vapor. This effect is related to the unique characteristics of phospholipid molecules to undergo hydration-dependent structural reorganizations and self-assembly. Using established techniques, diffraction characteristics of the membrane-grating can be made sensitive to molecules recognized by a biological probe immobilized on the bilayer. Interferometric lithography can give much finer engineering of biomembranes than can be accomplished with use of masks. This has the potential for high-density biosensor designs.
Dr. Anup Sharma
Department of Physics, Alabama A&M University
Abstract
Optical Nose: A Novel Mid-Infrared Laser System for Analyzing Gaseous Samples
For ultimate performance, optical detection of organic molecules has to be performed in the so-called "molecular fingerprint" region, located in the mid-infrared wavelength range between 2 and 20 mm. In this region, all organic molecules possess a dense series of strong, narrow-band absorption lines corresponding to rotational-vibrational transitions. By measuring the light absorption in a gas sample at a large number of different wavelengths in the fingerprint region, practically all such molecules can be identified and individual concentrations measured.
The "optical nose" simulates functions of biological olfaction, effectively mimics a magnified sense of smell and displays it in optical domain in a form of absorption patterns specific for each detected molecule.
UAB's optical nose laser system comprises an effective and compact "fiber-bulk" Er:YAG pump laser, a Cr2+:ZnSe seed laser, and a ZnGeP2-based high-power, narrow linewidth, ultra-broad and rapidly tunable Optical Parametric Generator in conjunction with compatible sensing and signal enhancing techniques to satisfy the challenging demands of real time analysis and quantification. Recent progress in developing the mid-IR laser system as well as possible practical applications will be discussed.
Dr. Sergey Mirov
Department of Physics, The University of Alabama in Birmingham
Abstract
Neutrino Oscillations in the Heavens and on Earth
Seventy years after the existence of the neutrino was postulated by Wolfgang Pauli, these elusive particles remain surrounded by mystery. One of the most fundamental questions about neutrinos is whether they have an identically vanishing mass, as assumed by the Standard Model of particle physics, or not. Direct mass measurements have proven to be extremely difficult to perform, and have yielded so far only upper limits. However, if neutrino (flavour) oscillations do happen, this would automatically imply that at least one of the three neutrinos (the electron, muon or tau neutrino) must have a non-zero mass. The present experimental data indicate that both the solar and atmospheric neutrino deficits can be explained by the phenomenon of neutrino oscillations, while the positive signal reported by the accelerator- based LSND experiment remains unconfirmed after the first round of measurements performed with MiniBooNE at the Fermi National Accelerator Laboratory. This talk reviews the current status of the neutrino oscillations experiments, and discusses briefly the latest results from MiniBooNE.
Dr. Ion Stancu
Associate Professor of Physics
Department of Physics and Astronomy
The University of Alabama
Abstract
Harnessing the Eclipse: Transiting Planets and KELT
The next stage of planet exploration has been propelled by the recent discovery of a number of transiting planets. I will discuss the current state of exoplanet discovery, describing various planet detection methods, focusing on transit surveys and the scientific value of transiting planets. I will summarize the benefits and challenges of searching for planets with transits, and describe the KELT project, a small telescope for planet detection. We have conducted several transit searches with KELT, and I will present recent results on variable stars and transit candidates from our survey. I will also talk about future instruments in the KELT program.
Born and raised in Cleveland, OH. Undergrad at Princeton where I worked with David Spergel and Bodhan Paczynski on Gamma-Ray-Bursts, and with Michael Strauss on detecting AGNs in the Sloan Digital Sky Survey. Graduated in 2000 and worked as a consultant in NYC before going to the OSU Astronomy PhD program in 2001. Worked on observations of the Galactic Center before doing theoretical work on planetary transits with Andy Gould and Scott Gaudi. Built the KELT telescope for transit surveys for PhD dissertation. Graduated in 2007 and joined Vanderbilt as a postdoc with the Vanderbilt Initiative in Data-Intensive Astrophysics (VIDA) program.
Dr. Joshua Pepper
Vanderbilt University
Abstract
Quantum Optics: From Basics to Daily Life Applications
During the last two decades quantum optics has become a field of research with many wonders. The counterintuitive phenomena predicted and experimentally tested in this field have already changed our perceptions of optics of materials. For example, it has been shown that one can make a strongly absorptive (opaque) medium transparent while leaving all the electrons in the ground states or we can trap an electron in an excited state despite the fact it naturally wants to decay down to the lower energy states. As exciting and potentially useful as they are, we have been largely unable to take advantage of these effects in our daily life applications including optical devices. In fact, today most of optical device designers and engineers deal with conventional devices with functionalities mostly dictated by the intrinsic optical and material properties of solids. In this talk, I will discuss how one can use some of the exotic effects verified in quantum optics as the main tools of design for various optical devices, including novel laser systems and integrated photonic circuits.
After a brief review of some major effects in quantum optics of atoms, I will explain how these effects can be realized in semiconductors. Then I will show how, when these effects are combined with the fact that we can engineer electron wavefunction in quantum wells, one can propose new photonic band gaps and laser systems. I will discuss fabrication steps of these devices based on conventional industry techniques and highlight their high compatibility for monolithic integration with other devices. At the end, I will touch a new method to generate active nanostructures using combined effects of nonlinear optical processes and semiconductor interface properties.
Dr. Seyed Sadeghi
University of Alabama in Huntsville
Abstract
Aurora on Ganymede
Jupiter's largest satellite Ganymede exhibits classic auroral emission, including a well defined auroral oval. Auroral emissions have been imaged both from the Keck telescope at visible wavelengths, and from the Hubble Space Telescope in the ultraviolet. The sparse number of observations to date show fascinating, and seemingly irreconcilable, features. This talk will summarize the existing imaging observations, as well as the modeling work done to date, which is based on the in situ magenetic field measurements made by the Galileo spacecraft.
Dr. Melissa McGrath
NASA Marshall Space Flight Center
Abstract
Heliophysics Science and the Moon
The Moon is immersed in a plasma environment — the local cosmos — that is "magnetized." It is threaded with magnetic fields that are often "frozen" into the plasma, a state of high electrical conductivity that
effectively couples the motions of the plasma and the magnetic field. This inherently strong coupling means that the structure and evolution of magnetic fields (of the Sun, of the Earth, and even of the Moon itself) play
an essential role in organizing and regulating the local environment of the Moon — the environment to be experienced by explorers. By working to understand, and so predict, the variations that occur from day to day, and from region to region, the productivity and overall success of future lunar robotic and manned missions can be significantly enhanced. This talk will articulate some of the viable investigations that can be pursued at the Moon that address topics of Solar and Space Physics. The content is based on a community based report in press entitled "Heliophysics Science and the Moon"
Dr. Jim Spann
NASA Marshall Space Flight Center
Abstract
China and India: A New Sputnik?
Federal Funding of Physical Sciences Research
Federal funding for the physical sciences has been stagnant for many decades, hindering scientific progress in many regards. Meanwhile, in the last decade, countries like China and India have made huge strides in improving their science and technology infrastructure, to the extent that U.S. leadership in many scientific fields is, or will soon be, challenged. The United States is also losing high-tech market share and jobs. Just as Sputnik jolted the U.S. into action 50 years ago, many believe that the current challenges require a Sputnik-like response. The American Physical Society is working hard to convince Members of Congress and the Administration to increase science research funding. In this talk, I will discuss challenges to U.S. science leadership and APS advocacy. I will also address whether physicists can have an impact in Washington.
Dr. Steve Pierson
American Physical Society
Abstract
Observe Matter Falling into a Black Hole
It has been well known that in the point of view of a distant observer, all in-falling matter to a black hole (BH) will be eventually stalled and "frozen'' just outside the event horizon of the BH, although an in-falling observer will see the matter falling straight through the event horizon. Thus in this "frozen star'' scenario, as distant observers, we could never observe matter falling into a BH, neither could we see any "real'' BH other than primordial ones, since all other BHs are believed to be formed by matter falling towards singularity.
Here we first obtain the exact solution for a pressureless mass shell around a pre-existing BH. The metrics inside and interior to the shell are all different from the Schwarzschild metric of the enclosed mass, meaning
that the well-known Birkhoff Theorem in its original form can only be applied to the exterior of a spherically symmetric mass. The metric interior to the shell can be transformed to the familiar Schwarzschild metric for a slower clock (compared to the case if the shell did not exist), indicating that outside, even spherically symmetric, matter influences interior metric, conceptually different from the Newtonian gravity. Another result is that there does not exist a singularity nor event horizon in the shell. Therefore the "frozen star''scenario is incorrect. We also show that for all practical astrophysical settings the in-falling time recorded by an external observer is sufficiently short that future astrophysical instruments may be able to follow the whole process of matter falling into BHs. The distant observer could not distinguish between a "real'' BH and a "frozen star'', until two such objects merge together. It has been proposed that electromagnetic waves will be produced when two "frozen stars'' merge together, but not so when two "real'' bare BHs merge together. However gravitational waves will be produced in both cases. Thus our solution is testable by future high sensitivity astronomical observations.
Dr. Shuang Nan Zhang
Tsinghua University and UAH
Abstract
Tornadoes: knowns, unknowns and future directions
This seminar will review the status of our scientific understanding of tornadoes and, in particular, the ways in which tornadoes form (i.e., the physics of tornado formation). Our understanding of tornadoes and tornadogenesis is incomplete, mainly because of the lack of detailed observations of the environmental conditions within and around thunderstorms that produce tornadoes. In order to fill this observational void, an extensive field study, the VORTEX2 project, is slated for 2009 and 2010. The goals of this study will be summarized.
Dr. Kevin Knupp
Department of Atmospheric Science, UAH
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