Bochum 2015 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 14: Poster Session - Theory and Modelling
P 14.17: Poster
Dienstag, 3. März 2015, 16:30–18:30, Foyer Audimax
Ion-acoustic Shocks with Reflected Ions — •Tatyana Liseykina1, Galina Dudnikova2, and Mikhail Malkov3 — 1Universität Rostock, Germany — 2University of Maryland, USA — 3University of California, San Diego, USA
Non relativistic collisionless shock waves are widespread in space and astrophysical plasmas and are known as efficient particle accelerators. Microscopically, these shocks are believed to be supported by suitable plasma waves that randomize particle trajectories in lieu of binary collisions. These waves are driven by non-equilibrium components of the plasma such as shock reflected or shock accelerated particles. We present the results of numerical modelling of an ion acoustic collisionless shock based on 1D kinetic approximation both for electrons and ions with a real mass ratio. Special emphasis is made on the shock reflected ions as the main driver of shock dissipation. The reflection efficiency, the distribution of reflected particles and the shock electrostatic structure are studied in terms of the shock parameters. An analytic solution for ion-acoustic collisionless shock with reflected ions is also presented. It extends a classic soliton propagating at the Mach numbers M < M* =1.6 beyond this value at which the soliton reflects the upstream ions. The soliton turns into a shock whose parameters are obtained in terms of the number of reflected ions. Applications to particle acceleration in geophysical and astrophysical shocks are discussed.