Faculty Research Focuses: Solar wind Solar physics Space weather Computational plasma physics Cosmic rays Magnetic turbulence and reconnection Interaction of the solar wind with the interstellar medium Interaction of the solar wind with the Earth and planets Low-temperature plasma physics and applications Exoplanets and stellar winds Space instrumentation development High-energy astrophysics including gamma rays and gravitational waves The Center for Space Plasma and Aeronomic Research or CSPAR has a very strong focus on the physics of space, related in an essential way to plasma physics as described further below. The physics of space begins in the upper atmosphere of the Earth, which is comprised of a mixture of a neutral gas made up of atoms such as primarily oxygen, nitrogen, and other minor species, and a gas of charged particles, such protons and electrons primarily together with minor heavier ions. A gas containing charged particles as well as neutral atoms is called a plasma and is completely unlike the plasma found in blood! The neutral and charged upper atmospheric gases are coupled through collisions with one another, and while both gases respond to the Earth’s gravitational field, the charged particles also respond to electromagnetic fields. CSPAR scientists and researchers study the role and physics of plasma throughout the universe, from the Earth’s upper atmosphere (aeronomy, ionosphere and magnetosphere) to the Sun and its atmosphere (solar physics) to the wind emitted by the Sun – the solar wind, a highly supersonic flow of plasma from the surface of the Sun to the interstellar medium with speeds that can reach 800 kilometers per second (space physics) to the structures and energetic particles in the solar wind and their effect and impact on the Earth (space weather), all the way to the local interstellar medium that surrounds the bubble created by the solar wind (the heliosphere). The interaction of the solar wind and the local interstellar medium represents a boundary between heliospheric or space physics and astrophysics. Finally, the interstellar and intergalactic media are the home to exploding stars (supernova), galactic jets, and colliding neutron stars and black holes, all of which can be characterized as high-energy astrophysics, producing gamma ray bursts, cosmic rays, and gravitational waves. All of the foregoing research areas are active and intense areas of investigation by theoretical, simulation and modeling, observational, and instrumental approaches. CSPAR scientists, researchers, postdocs, faculty members, graduate and undergraduate students are deeply engaged in one or more of these areas using some or all the described approaches. CSPAR scientists are also driving a major set of projects that address the role of plasma on Earth. It is not often realized but almost the entire IT industry, medical and manufacturing industry, aerospace, and more, including national and economic security, rely on plasma and its applications in one way or another. CSPAR scientists are exploring not only life-changing applications of plasma to society, bringing patents and new economic opportunities to Alabama, but they’re contributing to the development of a plasma-literate workforce. Plasma can make a difference! CSPAR scientists have a deep and abiding working relationship with the Marshall Space Flight Center (MSFC) in the areas of solar physics, high-energy astrophysics, space physics and space weather, and ionospheric-magnetospheric physics, as well as with the Department of Space Science. - Gary P. Zank Dr. Zank's Research Interests: Solar wind Solar physics Space weather Computational plasma physics Cosmic rays Magnetic turbulence and reconnection Interaction of the solar wind with the interstellar medium Interaction of the solar wind with the Earth and planets Low-temperature plasma physics and applications Exoplanets and stellar winds CSPAR Faculty Dr. Laxman Adhikari Research Focus: Solar wind; Turbulence The corona, the outermost layer in the solar atmosphere, is formed by heated plasma that is partially confined by strong open and closed magnetic field lines, which control the plasma and pressure density. The solar corona is heated to temperatures of millions of degrees Kelvin, giving rise to the solar wind, whose speed transitions from subsonic to supersonic. The solar wind continues to expand until its ram pressure is balanced by the pressure of the partially ionized interstellar medium (ISM) plasma, forming a cavity in the ISM known as the heliosphere. Turbulence is a common phenomenon in the solar wind and is believed to play a key role in several physical mechanisms. Dr. Adhikari studies the evolution of turbulence throughout the heliosphere, and its impact on various phenomena, including coronal heating and solar wind acceleration in the solar atmosphere; proton and electron heating in the solar wind from the inner to outer heliosphere; solar wind entropy variations throughout the heliosphere, and the mean free paths of cosmic rays throughout the heliosphere. Anisotropy is an important property of solar wind fluctuations, describing the changes in the properties of turbulence to direction relative to the large-scale magnetic field. Understanding the nature of anisotropic turbulence enables a more accurate explanation of solar corona heating and solar wind heating. Dr. Adhikari studies the radial evolution of turbulence anisotropy in terms of energy, correlation length, and cascade rates by analyzing data from Parker Solar Probe and Solar Orbiter, along with applying nearly incompressible turbulence transport model equations in the inner heliosphere. In the outer heliosphere, interactions between the solar wind protons and interstellar neutral hydrogen (ISN H) atoms lead to the formation of H+ pickup ions (PUIs). These H+ PUIs play an important role in governing solar wind dynamics in this region. The noticeable effects of the presence of H+ PUIs are the gradual decrease in solar wind speed and an increase in the temperatures of solar wind protons and electrons. To investigate the effect of H+ PUIs formed through these interactions, Dr. Adhikari develops a four-fluid model that includes protons, electrons, H+ PUIs, and ISN H atoms while incorporating turbulence transport equations. Dr. Haihong Che Research Focus: Low-temperature plasma physics and applications in Solar physics; Solar wind and magnetospheric plasma; Computational plasma physics Dr. Che's research focuses on nonlinear plasma kinetic physics in heliophysics and astrophysics. Specifically, studying 1) magnetic reconnection which powers solar flares, magnetospheric substorms and other astrophysical explosive events like gamma ray bursts, 2) coherent plasma emissions which are associated with solar radio bursts, and 3) plasma instabilities and turbulence which play essential role in the solar wind and corona heating and particle acceleration in solar flares, magnetospheric substorms and astrophysical explosive events. Using high-performance PIC simulations and kinetic theory, Dr. Che investigates how multi-scale wave interactions driven by kinetic instabilities accelerate/transport particles and generate emissions, advances the theoretical framework with analytical methods, formulate models for interpretation and prediction for the solar, solar wind and magnetospheric observations. Dr. Vladimir Florinski Research Focus: Computational plasma physics; Cosmic rays; Interaction of the solar wind with the interstellar medium Computational plasma physics Dr. Florinski is a practitioner of particle-mesh kinetic simulations describing a small (typically a few thousand km) parcel of space plasma with magnetic field, and a population of energetic charged particles. He used hybrid (kinetic-fluid) simulations to investigate the behavior of pickup ions outside the boundary of the heliosphere, where they form an unstable ring velocity distribution. A relatively stable ring is required to produce the enhanced outflow of hydrogen atoms from the region known as the IBEX ribbon. Florinski's work drew attention to the stability problem, and it continues to inspire research on kinetic instabilities in weakly collisional space environments. Computer codes, tools, and techniques developed with the help of this reseach are now available to student via the Computational Physics graduate curriculum in the Department of Space Science. Cosmic rays Cosmic rays are messengers from the distant parts of the Galaxy, where they are though to be energized by multiple encounters with shock waves produced by supernova explosions. Florinski studies the interaction between low-energy (under 1 GeV) galactic cosmic rays with the heliosphere on the large scales, from the solar system boundary to the Earth's orbit. He led multiple studies aimed at understanding cosmic ray transport in the heliosheath region, which is the outermost magnetic barrier protecting the planets from this harmful galactic radiation, using computer models he developed over the years. This work led to a better understanding of cosmic ray intensity mediation by turbulent magnetic fields and recurring solar wind flow structures such as magnetic polarity sectors and corotating interaction regions. Florinski's study of a magnetic bottle like structure in the very local interstellar medium created a new perspective on cosmic ray trapping by the stellar astrospheres. Using theory and models, Florinski is also contributing to the understanding of the origin of anomalous cosmic rays and their influence on the solar wind. Interaction of the solar wind with the interstellar medium Our Sun is surrounded by a giant bubble of rarefied plasma called the heliosphere, created by outflow of the solar wind and pushing against the denser environment of the interstellar cloud that our solar system is embedded in. Florinski develops virtual models of the heliosphere using unstructured simulation grids known as geodesic meshes. His recent work is focused on including the effects of plasma temperature anisotropy on the structure of the interface and the properties of waves and turbulent fluctuations generated in such anisotropic environments. Dr. Qiang Hu Research Focus: Solar wind Dr. Hu's current research focuses on the analysis of an important type of magnetic structures in the solar wind: magnetic flux ropes. These structures possess a wide range of scale sizes, ranging from a few thousand kilometers across to a cross-section size up to about a few tenths of the distance between Sun and Earth. The largest flux ropes among them correspond to the coronal mass ejections that erupt from the Sun and often can be observed by multiple spacecraft missions. The analysis method employed is a unique, physics-based model that provides a more general quantitative characterization of the magnetic field configuration of a flux rope derived directly from in-situ measurements along the spacecraft path across the structure. This enables a broad application of this method to all spacecraft missions in space that return in-situ measurements of magnetic field and plasma parameters. A designated website, fluxrope.info, as the name indicates, contains a database in tabulated form of the flux rope structures identified from various spacecraft datasets. Dr. Jakobus le Roux Research Focus: Cosmic rays; Computational plasma physics; Space weather Cosmic rays Research interests: Basic kinetic transport theory of energetic charged particles in nonuniform high-conductivity (collisionless) plasma flows; quasi-linear, and nonlinear kinetic theory of energetic charged particle scattering and stochastic acceleration in the intermittent low-frequency turbulent electromagnetic fields of, e.g., Alfven waves and quasi-2D turbulence containing small-scale magnetic flux ropes in the solar wind; kinetic theory of energetic charged particle acceleration at collisionless heliospheric shocks; the development of tempered fractional kinetic transport theories to model non-diffusive energetic particle propagation and acceleration in response to intermittent low frequency electromagnetic turbulence as observed the solar wind; modeling the observed behavior of solar energetic particles, interstellar pickup ions, anomalous and galactic cosmic rays in the heliosphere. Computational plasma physics Interests: Applying finite difference and finite volume numerical methods to solve kinetic transport equations, such as the focused and Parker transport equations, and transport equations for Alfven waves and quasi-2D turbulence to simulate observed behavior of solar energetic particles, interstellar pickup ions, and anomalous and galactic cosmic rays in the heliosphere. Space weather Interests: simulating the diffusive shock acceleration of solar energetic particles at coronal-mass ejection-driven shocks using focused transport theory. Dr. Subramania Athiray Panchapakesan Research Focus: Solar physics; Space instrumentation development Dr. Panchapakesan is a astrophysicist specializing in plasma heating and energy transport in both flaring and non-flaring solar active regions. These active regions, characterized by complex and concentrated magnetic fields in the solar atmosphere, are sites where vast amounts of magnetic energy are converted into kinetic energy and plasma heating through processes that are still not fully understood. his research aims to explain these phenomena using multi-wavelength observations in the ultraviolet and X-ray regimes, combining narrowband imaging and wide-field imaging spectroscopy with theoretical modeling. A key aspect of his work involves developing methods to analyze data from slitless spectroscopy instruments—known as overlappograms. This novel technique enables more quantitative characterization of plasma properties across a wide field of view. In addition, he contributes to the development of new instruments for high-energy solar observations, particularly in the testing and calibration of X-ray mirrors and detectors. These instruments are often flown on sounding rockets and CubeSats as precursors to larger space-based observatories. In collaboration with NASA Marshall Space Flight Center (MSFC), they pioneered the development of solar X-ray telescopes through the MaGIXS (Marshall Grazing Incidence X-ray Spectrometer) mission, which has completed two successful sounding rocket flights from White Sands Missile Range. The success of MaGIXS has paved the way for a new generation of solar observatories, and he is actively engaged in their development through scientific collaborations. Dr. Nikolai Pogorelov Research Focus: Solar wind, Solar physics, Space weather; Computational plasma physics; Cosmic rays; Magnetic turbulence and reconnection; Interaction of the solar wind with the local interstellar medium Dr. Pogorelov's scientific interests encompass a broad range of plasma physics, including space physics. While starting his career as an aerodynamicist performing simulations of chemically-reacting flows over complex-shaped bodies at high angle of attack, he returned to magnetohydrodanamics (MHD), which was the subject of his Master of Science thesis. The applications involved the solar wind (SW) interaction with the local interstellar medium (LISM) and accretion of interstellar matter on gravitating objects. While developing software for solving these problems he became interested in the theory of hyperbolic equations, which resulted in the publication of a book "Mathematical Aspects of Numerical Solution of Hyperbolic Systems" (CRC Press, Boca Raton, FL, USA). Of his particular interest is the theory on nonevolutionary MHD shocks and uniqueness of weak solutions to ideal MHD equations. We perform data-driven simulations of the SW-LISM interaction with different levels of model sophistication, particularly, using photospheric magnetogram data to develop the boundary conditions for the solar corona and heliosphere models. Our simulations can be performed in a multi-fluid approximation or using a kinetic, Monte Carlo, treatment of the neutral atom transport. In addition to including H and He atoms, we have also developed a model where electrons, H+ (thermal and nothermal), He+, and He++ ions are treated as separate fluids. Special attention is paid to kinetic processes accompanying nonthermal, pickup ion (PUI) crossing collisionless shocks, e.g., the heliospheric termination shock. Extensive kinetic (test particle, hybrid, and full-particle simulations allowed us to derive the Rankine-Hugoniot type boundary conditions at the heliospheric termination shock and incorporate them with the global MHD model of the SW-LISM interaction. We are able to solve Reynolds-averaged MHD equations accompanied by different turbulence models to account for heating of the thermal ions by the turbulence generated by PUIs. We are applying different solar coronal models, and also developing new ones to provide data-driven, time-dependent boundary conditions for our heliospheric models. To improve space weather forecasts and quantify uncertainties in our predictions, we are performing ensemble modeling and use machine learning (ML) techniques to correlate errors at spacecraft and remote measurements in the space between the Sun and Earth with those at L1, This approach proved to be very efficient, so we are extending the database of available measurements with the purpose of ultimately making space weather forecasts, e.g., coronal mass ejection (CME) arrival at Earth and magnetic field CMEs are carrying, reliable. We are performing simulations of the TeV-PeV Galactic cosmic ray (GCR) transport towards Earth. Comparison of the simulated GCR anisotropy with the measurements from the Tibet, IceCube, and HAWC observatories allows us to (1) constrain the SW-LISM interaction models and (2) provide the astrophysical community with GCR fluxes free from the heliospheric influence. This research is possible because of the software developed by our laboratory. Multi-Scale Fluid-Kinetic Simulation Suite allows us to obtain self-consistent solutions of MHD equations and kinetic Boltzmann equations. Simulations are performed with the second order of accuracy in space and time using adaptive mesh refinement (AMR). A new generation software, HelioCubed, does this with the 4-th order of accuracy on cubed-sphere grids, which increases the efficiency of simulations dramatically and ensures adequate resolution near the polar regions. Substantial efforts are made to make the developed software public. Dr. Robert D Preece Research Focus: High-energy astrophysics including gamma rays and gravitational waves Dr. Preece's research involves the analysis of gamma-ray bursts (GRBs), which are enigmatic cosmological explosions of high-energy radiation that occur about once a day in the universe. To facilitate their study, he has been involved in two of NASA’s gamma-ray observatories, the Compton Observatory, with the Burst and Transient Source Experiment (BATSE) from 1991 to 2000, and the Fermi Gamma-Ray Burst Monitor (GBM), launched in 2008 and on-going. he studies the spectroscopy of GRBs to determine the source of their prodigious energy and the mechanism of their emission. Dr. Lingling Zhao Research Focus: Solar wind; Space weather; Cosmic rays; Magnetic turbulence and reconnection; Interaction of the solar wind with the interstellar medium Dr. Zhao's research focuses on the interplay of heliospheric processes, including magnetized turbulence, waves, shocks, and energetic particles, by integrating theoretical models with observations from Parker Solar Probe and Solar Orbiter. Her research on the solar wind aims to understand the formation, acceleration and evolution of the solar wind by analyzing observations from new missions, in particular in the near-solar region where turbulence transitions from the sub-Alfvén regime to the super-Alfvén regime. Her research on space weather phenomena is related to the extreme energetic particles associated with strong shocks. Her work also explores cosmic ray modulation by the solar wind and its embedded magnetic field, as well as magnetic turbulence and reconnection processes that influence energy transfer and particle transport. Additionally, she investigates how the solar wind interacts with the interstellar medium, shaping the global structure of the heliosphere and its role in the interstellar medium turbulence observation. These interconnected studies contribute to a unified understanding of heliospheric dynamics and their implications for space weather and deep-space exploration.