title: Electron acceleration in a nonrelativistic shock with very high Alfvén Mach number.
abstract: Electron acceleration associated with various plasma kinetic instabilities in a nonrelativistic shock with very high Alfvén Mach number (M(A)~45) is revealed by means of a two-dimensional fully kinetic particle-in-cell simulation. Electromagnetic (ion Weibel) and electrostatic (ion-acoustic and Buneman) instabilities are strongly activated at the same time in different regions of the two-dimensional shock structure. Relativistic electrons are quickly produced predominantly by the shock surfing mechanism with the Buneman instability at the leading edge of the foot. The energy spectrum has a high-energy tail exceeding the upstream ion kinetic energy accompanying the main thermal population. This gives a favorable condition for the ion-acoustic instability at the shock front, which in turn results in additional energization. The large-amplitude ion Weibel instability generates current sheets in the foot, implying another dissipation mechanism via magnetic reconnection in a three-dimensional shock structure in the very-high-M(A) regime.
authors: Department of Physics, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors: Y
authors: Y
authors: Matsumoto
authors: T
authors: T
authors: Amano
authors: M
authors: M
authors: Hoshino