Stanford School of Medicine
Radiation Oncology–

Ulrich Langner

Ph.D. in Heliospheric Physics,
Potchefstroom University for Christian Higher Education, South Africa, 2004

Research

The main topic of my Ph.D. and previous postdoctoral positions was to study the solar wind termination shock’s structure and dynamics and its effects on the modulation, propagation, and distribution of various galactic and anomalous cosmic ray species in the heliosphere. To do this the Parker transport equation was solved in an existing two dimensional model of the heliosphere. This model was improved in these studies to include shock acceleration of cosmic rays at the solar wind termination shock, state-of-the-art diffusion coefficients, and asymmetrical boundaries in the heliosphere, and could be used to solve for various cosmic ray species simultaneously. At Stanford, I am working with Dr. Paul Keall on the development of a simulation package for evaluating motion-conditioned 4D CT acquisition using available respiratory motion datasets.


Publications

  1. Langner, U. W., M. S. Potgieter, H. Fichtner, and T. Borrmann, Effects of solar wind speed changes in the heliosheath on the modulation of cosmic ray protons, Astrophys. J., 640(2), 1119-1134, doi: 10.1086/500162, doi: 10.1029/2005JA011066, 2006.
  2. Langner, U. W., M. S. Potgieter, H. Fichtner, and T. Borrmann, Modulation of anomalous protons: Effects of different solar wind speed profiles in the heliosheath, J. Geophys. Res., 111(A1), A01106, 2006.
  3. Langner, U.W., and M. S. Potgieter, Effects of the position of the solar wind termination shock and the heliopause on the heliospheric modulation of cosmic rays, Adv. Space Res., 35(12), 2084-2090, doi: 10.1016/j.asr.2004.12.005, 2005.
  4. Langner, U. W., and M. S. Potgieter, The heliospheric modulation of cosmic ray protons during increased solar activity: Effects of the position of the solar wind termination shock and of the heliopause, Annales Geophysicae, 23, 1499-1504, 2005.
  5. Langner, U. W., and M. S. Potgieter, Modulation of galactic protons in an asymmetrical heliosphere, Astrophys. J., 630(2), 1114-1124, doi:10.1086/431547, 2005.
  6. Potgieter, M.S. and U. W. Langner, Modulation of cosmic rays: Perpendicular diffusion and drifts in a heliosphere with a solar wind termination shock, Adv. Space Res., 35(4), 554-561, doi: 10.1016/j.asr.2005.01.008, 2005.
  7. Potgieter, M.S. and U. W. Langner, Modulation and acceleration of anomalous protons in the outer heliosphere, Adv. Space Res., 34(1), 132-137, doi:10.1016/j.asr.2003.02.062, 2004.
  8. Potgieter, M. S., and U. W. Langner, Heliospheric modulation of cosmic ray positrons and electrons: Effects of the heliosheath and the solar wind termination shock, Astrophys. J., 602(2), 993-1001, doi:10.1086/381148, 2004.
  9. Potgieter, M. S., and U. W. Langner, The heliospheric modulation of cosmic ray Boron and Carbon, Annales Geophysicae, 22, 3729-3740, 2004.
  10. Langner, U. W., M. S. Potgieter, and W. R. Webber, Modelling of `barrier' modulation for cosmic ray protons in the outer heliosphere, Adv. Space Res., 34(1), 138-143, doi:10.1016/j.asr.2003.02.058, 2004.
  11. Langner, U. W., and M. S. Potgieter, Effects of the solar wind termination shock on charge-sign dependent cosmic ray modulation, Adv. Space Res., 34(1), 144-149, doi:10.1016/j.asr.2003.01.031, 2004.
  12. Langner, U. W., and M. S. Potgieter, Solar wind termination shock and heliosheath effects on the modulation of protons and anti-protons, J. Geophys. Res., 109(A01103), doi:10.1029/2003JA010158, 2004.
  13. Langner, U. W., and M. S. Potgieter, Effects of the solar wind termination shock and heliosheath on the heliospheric modulation of galactic and anomalous Helium, Annales Geophysicae, 22, 3063-3072, 2004.
  14. Langner, U. W., M. S. Potgieter, and W. R. Webber, Modulation of cosmic ray protons in the heliosheath, J. Geophys. Res., 108(A10), 8039-8048, doi:10.1029/2003JA009934, 2003.
  15. Potgieter, M.S., and U. W. Langner, Modulation of anomalous protons with increasing solar activity, Adv. Space Res., 32(4), 687-692, doi:10.1016/S0273-1177(03)00359-4, 2003.
  16. Langner, U. W., O. C. de Jager, and M. S. Potgieter, On the local interstellar spectrum for cosmic ray electrons, Adv. Space Res., 27(3), 517-522, 2001.
  17. Potgieter, M. S., U. W. Langner, and S. E. S. Ferreira, Cosmic ray electron to positron ratios in the heliosphere, Adv. Space Res., 27(3), 523-528, 2001.

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