A Perturbation Method and Its Application to Obliquely Propagating Nonlinear Alfvén Wave

Abstract

A procedure to the coordinate stretching and the perturbation expansion for the reductive perturbation method is proposed to analyze the nonlinear wave behaviors in dispersive medium. The method is applied to the nonlinear Alfvén wave propagating in an oblique direction to the static magnetic field in cold plasmas. Although the wave is described by a linear equation for some physical quantities, the nonlinearity appears in the relation among the other quantities for considerably large amplitude. These outstanding features are much different from other waves in plasmas.