Asymptotic solutions of waves in inhomogeneous plasma with longitudinal magnetic field

Abstract

The asymptotic solutions to the second-order differential equations governing the wave propagation in inhomogeneous plasma are given where the external magnetic field is assumed to be in the longitudinal direction. The zero-, first-, second-, third-, fourth,- and fifth-order approximations are explicitly given. It is further shown that the third-order asymptotic approximation agrees with the WKBJ approximation. Numerical results for a linear profile of electron concentration are given, and they are found to improve the WKBJ approximation.