The instabilities induced by electrostatic fields and gradients in a plasma shock front

The linear instabilities induced by the electrostatic fields and gradients of equilibrium parameters in a plasma shock front are analyzed for the plasma shock structure. Small perturbations as well as the steady-state shock structure are described by a set of coupled two-fluid and Poisson equations. The dispersion relations are obtained at high frequency in two cases, in which the wave vectors are, respectively, parallel and perpendicular to the shock propagation direction. The imaginary parts of the frequency (growth rates) of the instabilities are dependent on the fields and the gradients. (c) 2008 American Institute of Physics.