Dr. Jacob Heerikhuisen

Associate Professor, Space Science Department
Associate Director, Center for Space Plasma and Aeronomic Research


I study the interaction of the solar wind with the interstellar medium using a variety of computational tools developed by our team of heliospheric modelers in the UAH Space Science department and CSPAR. In particular, I have developed a Monte-Carlo code that tracks hydrogen atoms as they pass from interstellar space through the heliosphere. When these charge-exchange with the plasma, momentum and energy source terms are generated that are fed back into the MHD equations that we solve for the plasma. At the same time, some charge-exchange collisions produce energetic neutral atoms (ENAs) that travel large distances through the heliosphere. I work closely with the team from NASA's IBEX satellite which detects ENAs and generates all-sky maps. To relate these 2D maps to the global structure of the heliosphere requires accurate models which we develop.


Comparison between IBEX spacecraft data (left) of the unexpected “ribbon” of ENAs, plotted so as to highlight its circularity. Middle and right show simulated ENA maps for two different interstellar magnetic field strengths, suggesting that the field strength is likely less than 4 μG (see paper 1).

ena spectra

ENA spectra computed by graduate student Zirnstein on the basis of assuming a particular breakdown for different populations of pick-up ions, assuming that the total energy and density add up to the MHD-neutral simulation results (see paper 2).


  • Ph.D., Applied Mathematics, University of Waikato, New Zealand, 2001
  • M.S., Applied Mathematics, University of Waikato, New Zealand, 1997
  • B.S., Applied Mathematics, University of Waikato, New Zealand, 1996

Classes Taught

Recent grants & contracts

  • Global modeling of ENA fluxes in the heliosphere (NASA NNH08ZDA001N-HGI) - $418,075
  • Tracking energetic neutral atoms from the inner heliosphere back to the source (NASA NESSF11) - $90,000
  • Grassroots effort to diversify solar and heliospheric physics (NSF GEO-LSAMP) - $40,001
  • REU site: solar and heliospheric physics at UAH and MSFC (NSF Solar Terrestrial) - $353,356

Selected Publications

  • Zirnstein, E. J., H. O. Funsten, J. Heerikhuisen, D. J. McComas, N. A. Schwadron, and G. P. Zank. “Geometry and Characteristics of the Heliosheath Revealed in the First Five Years of Interstellar Boundary EXplorer Observations.” The Astrophysical Journal 826, no. 1 (July 20, 2016): 58. doi:10.3847/0004-637X/826/1/58.
  • Zirnstein, E. J., J. Heerikhuisen, H. O. Funsten, G. Livadiotis, D. J. McComas, and N. V. Pogorelov. “Local interstellar magnetic field determined from the Interstellar Boundary Explorer ribbon.” The Astrophysical Journal 818, no. 1 (February 10, 2016): L18. doi:10.3847/2041-8205/818/1/L18.
  • Effects of Solar Wind Speed on the Secondary Energetic Neutral Source of the Interstellar Boundary Explorer Ribbon, by E J Zirnstein, J Heerikhuisen, H O Funsten, D J McComas, Astron. Astrophys., 586, A31, 2016.
  • Toward More Realistic Analytic Models of the Heliotail: Incorporating Magnetic Flattening via Distortion Flows by J Kleimann, C Roeken, H Fichtner, J Heerikhuisen, Astrophys. J., 816, p14, 2016.
  • The Heliotail, N V Pogorelov S N Borovikov, J Heerikhuisen, M Zhang, “Astrophys. J., 812, L6, 2015.
  • Structure of the Interstellar Boundary EXplorer Ribbon from Secondary Charge-Exchange at the Solar-Interstellar Interface by E J Zirnstein, J Heerikhuisen, D J McComas, Astrophys. J. Lett., 804, L22, 2015.
  • Simulations of a Dynamic Solar Cycle and its Effects on the Interstellar Boundary Explorer Ribbon and Globally-Distributed Energetic Neutral Atom Flux, by E J Zirnstein, J Heerikhuisen, N V Pogorelov, D J McComas, M A Dayeh, Astrophys. J., 804, p5, 2015.
  • Latitudinal and Energy Dependence of Energetic Neutral Atom Spectral Indices Measured by the Interstellar Boundary Explorer, by M I Desai, F Allegrini, M A Dayeh, H Funsten, J Heerikhuisen, D J McComas, S A Fuselier, N Pogorelov, N A Schwadron, G P Zank, E J Zirnstein, Astrophys. J., 802, p100, 2015.
  • Lyman-alpha Radiation Pressure in the Heliosphere: Results from a 3D Monte Carlo Radiative Transfer Simulation, by B Fayock, G P Zank, J Heerikhuisen,C R Gilbert, K Scherer, Journal of Physics: Conference Series, 642, 2015.
  • Funsten, H.Õ., Bzowski, M., Cai, D.M., Dayeh, M., DeMajistre, R., Frisch, P.C., Heerikhuisen, J., Higdon, D.M., Janzen, P., Larsen, B.A., Livadiotis, G., McComas, D.J., Möbius, E., Reese, C.S., Roelof, E.C., Reisenfeld, D.B., Schwadron, N.A., Zirnstein, E.J. (2015). Symmetry of the IBEX Ribbon of Enhanced Energetic Neutral Atom (ENA) Flux. The Astrophysical Journal, 799, 68.
  • Burlaga, L.F., Ness, N.F., Florinski, V. A., Heerikhuisen, J. (2014). Magnetic Field Fluctuations Observed in the Heliosheath and Interstellar Magnetic Field by Voyager 1 at 115.7-124.9 AU during 2011-2013. The Astrophysical Journal, 792, 134.
  • Pogorelov, N.V., Borovikov, S.N., Heerikhuisen, J., Kim, T.K., Zank, G.P. (2014). Time-dependent Processes in the Sheath Between the Heliospheric Termination Shock and the
  • Zank, G.P., Heerikhuisen, J., Wood, B.E., Pogorelov, N.V., Zirnstein, E., McComas, D.J. (2014). Heliospheric Structure: The Bow Wave and the Hydrogen Wall. In Hu, Q.; Zank, G.P. (Ed.), Outstanding Problems in Heliophysics: From Coronal Heating to the Edge of the Heliosphere (vol. 484, pp. 255).
  • Gamayunov, K., Zhang, M., Pogorelov, N., Heerikhuisen, J., Rassoul, H. (2014). Turbulent Heating of the Core Solar Wind Protons in the Outer Heliosphere. In Hu, Q.; Zank, G.P. (Ed.), Outstanding Problems in Heliophysics: From Coronal Heating to the Edge of the Heliosphere (vol. 484, pp. 49).
  • Heerikhuisen, J., Zirnstein, E. J., and Pogorelov, N. V., κ-distributed protons in the solar wind and their charge-exchange coupling to energetic hydrogen, Journal of Geophysical Research, 120, 1516 (2015).
  • Burlaga, L. F., Ness, N. F., Florinski, V., and Heerikhuisen, J., Magnetic field fluctuations observed in the heliosheath and interstellar magnetic field by Voyager 1 at 115.7-124.9 AU during 2011-2013, Astrophysical Journal, 792, 134 (2014).
  • Heerikhuisen, J., Zirnstein, E. J., Funsten, H. O., Pogorelov, N. V., and Zank, G. P., The effect of new interstellar parameters on the heliosphere and ENAs from the interstellar boundary, Astrophysical Journal, 784, 73 (2014).
  • Zirnstein, E. J., Heerikhuisen, J., Zank, G. P., Pogorelov, N. V., McComas, D. J., and Desai, M. I., Charge-exchange coupling between pickup ions across the heliopause and its effect on energetic neutral hydrogen flux, Astrophysical Journal, 783, 129 (2014).
  • Desai, M. I., Allegrini, F. A., Bzowski, M., Dayeh, M. A., Funsten, H. O., Fuselier, S. A., Heerikhuisen, J., Kubiak, M. A., McComas, D. J., Pogorelov, N. V., Schwadron, N. A., Sokol, J. M., Zank, G. P., and Zirnstein, E. J., Energetic neutral atoms measured by the Interstellar Boundary Explorer (IBEX): Evidence for multiple heliosheath populations, Astrophysical Journal, 780, 11 (2014).
  • Heliopause. In Pogorelov, N.V.; Audit, E.; Zank, G.P. (Ed.), 8th International Conference of Numerical Modeling of Space Plasma Flows (ASTRONUM 2013) (vol. 488, pp. 167).