Oblique ion acoustic excitations in an ultra-relativistic degenerate dense magnetoplasma

Abstract

The linear and nonlinear propagation of ion acoustic waves is considered in a degenerate magnetoplasma, composed of relativistic degenerate electrons and an inertial ion fluid. A linear dispersion relation is derived in the linear approximation. The Sagdeev pseudopotential approach is used to investigate the properties of arbitrary amplitude, obliquely propagating ion acoustic solitary waves. The expression for the lower and upper Mach numbers for the existence of magnetized ion acoustic solitons has also been derived. The significant influence on the properties of soliton structures of relevant physical parameters, such as the plasma number density, the obliqueness (the angle between soliton propagation direction and magnetic field), and the soliton speed is also investigated. At the end, analytical results are supplemented through numerical analysis by using typical representative parameters consistent with degenerate and ultra-relativistic magnetoplasmas of astrophysical regimes.