Bremen 2000 – wissenschaftliches Programm
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EP: Extraterrestrische Physik
EP 9: Sonne und Heliosph
äre III
EP 9.8: Vortrag
Mittwoch, 22. März 2000, 17:45–18:00, H1
Injection and acceleration of suprathermal ions at perpendicular shocks: a self-consistent model of the solar wind termination — •H. Fichtner1, J.A. le Roux2, and G.P. Zank2 — 1Ruhr-Universität Bochum, Germany — 2Bartol Research Institute, University of Delaware, USA
We present first results of a self-consistent model of the multiple reflection and subsequent acceleration of suprathermal ions at the solar wind termination shock. Besides a determination of the injection efficiency of pick-up ions (PUIs) into the process of diffusive shock acceleration, we investigate the structure of the termination shock in detail. We find the shock to experience modest mediation by the accelerated PUIs if its ramp/subramp width is equal to the thermal electron inertial length. For a distribution of multiply reflected ions fMRI ∝ p−3 the fraction of reflected PUIs is ∼14% and the shock compression ratio is reduced to ∼2.9. Stronger mediation is predicted for a harder MRI spectrum or a larger fraction of reflected PUIs. Accelerated pick-up protons reach a maximum energy of at least ∼220-240 keV which is in tune with recent hybrid test particle calculations. Such extended MRI spectra for pick-up protons, if realistic, might enable a direct injection of these particles into standard diffusive shock acceleration at the termination shock. Thus, this model also provides a quantitative basis for a study of anomalous cosmic rays.