Nonlinear dispersive Alfven waves in dusty plasma in the transition limit, α~1

Abstract

Localized nonlinear structures associated with dispersive Alfven waves are investigated in dusty plasma in the transition limit, i.e., α≡(β/2Q)~1, where β is the ratio of thermal to magnetic pressure and Q is electron to ion mass ratio. Sagdeev pseudopotential is obtained from the basic governing equations, which is then numerically solved to study the existence and the behaviors of the nonlinear structures. It is found that both compressive and rarefactive solitons can coexist above and below certain critical α- values determined by the wave direction cosine (KZ) and the Mach number (M); and the compressive (rarefactive) solitons are much wider than the rarefactive ones for the case M<KZ (M>KZ). In addition, the rarefactive solitons are found to be converted into rarefactive double layers, for the case M>KZ, if the dust grains are negatively charged and their density exceeds certain critical value.