Dudnikova G.I.   Liseykina T.V.   Vshivkov V.A.  

Ion-acoustic shocks with reflected ions: рarticle-in-cell and hybrid simulations.

Reporter: Liseykina T.V.

Numerical simulation of  the ion-acoustic collisionless shock with self-consistently reflected ions is obtained. Three different models are considered. The first model corresponds to the conventional Boltzmannian electron distribution in which case the shock Mach number only insignificantly increases with the number of reflected ions from Max number M=1.6 (no reflection) to M=1.8 (strong reflection). The second model corresponds to adiabatically trapped electrons producing a stronger increase Max number from M=3.1 to M= 4.5. Both these hybrid  models are based on kinetic approximation for ion plasma component. The third model is based on kinetic approximation  of ions and electrons as well. Particle-in-cell (PIC) method is used for solving Vlasov equations. The electrostatic field is obtained by direct integration of the charge density, which in turn is calculated from the individual particle positions. The reflection efficiency, velocity distribution of reflected particles and the shock electrostatic structure are studied. This research is relevant to the electrostatic shock propagation in laser-produced plasmas, especially to the monoenergetic ion beam generation, to the ion injection into the diffusive shock acceleration in astrophysical shocks, and other shock related processes in astrophysical and space plasmas.

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