Ion-acoustic double layers in a magnetized low-beta plasma consisting of warm adiabatic ions, non-thermal electrons and electrons with a vortex-like distribution

Abstract

Ion-acoustic double layer structures propagating obliquely to an external uniform magnetic field have been considered in a low-beta plasma consisting of warm adiabatic ions, non-thermal electrons (due to Cairns et al) which generate fast energetic electrons, and electrons with a vortex-like distribution (due to Schamel), taking care of both free and trapped electrons, immersed in a uniform and static magnetic field. A combined Schamel's modified Korteweg–de Vries–Zakharov–Kuznetsov (S-KdV-ZK) equation more efficiently describes the nonlinear behavior of an ion-acoustic wave when the vortex-like velocity distribution function of electrons approaches the isothermal velocity distribution function of electrons, i.e. when the contribution of trapped electrons tends to zero. This combined S-KdV-ZK equation admits a double layer solution. The condition for the existence of this double layer solution has been discussed with respect to different parameters of the system.