Arbitrary Amplitude Double Layers in Dust Kinetic Alfvén Wave Plasmas with κ-Distributed Electrons

Abstract

An investigation has been done to study the effects of κ-distributed electrons on the waves with arbitrary amplitude of magnetized plasma in the presence of warm ions and negatively charged dust particles. The kappa distribution (κ > 3/2), which represents a velocity distribution, contains high energy tail but nears to the Maxwell–Boltzmann distribution as κ → ∞. In this work, by using the non-perturbation technique (i.e., Sagdeev pseudopotential analysis), a suitable mathematical expression for the arbitrary amplitude double layers in dust kinetic Alfvén waves is formulated. Using the standard numerical values for different plasma parameter related to it, the Sagdeev Potential (SP) has been calculated for the plasma waves. It is observed that the spatial index κ plays a substantial role in finding the size and shape of double layers. Depth of double layers increases with decreasing kz, keeping ω fixed. For this parameter set, the double layer does not exist when M ≤ 1.1. This theoretical study may be helpful for explaining some of recent in situ observations (e.g., Freja, Cassini) in space plasmas, where one of its constituents is kappa distributed electron.