Dust acoustic double layers in a magnetized dusty self-gravitating plasma with superthermal particles

作者：Sabetkar Akbar; Dorranian Davoud^*

来源：Physics of Plasmas, 2016, 23(8): 083703.

DOI：10.1063/1.4960298

Our prime objective of this paper is to examine the parametric regimes for the existence and polarity of dust acoustic double layers (DADLs) and its solitary structures arising from a magnetized self-gravitating opposite polarity dust-plasma (OPDP) model. The constituents of the OPDP model are two species of positively and negatively charged dust grains, Maxwellian electrons and kappa distributed ions. Contributions of gravitational force only on dust grains are taken into account. For weakly nonlinear analysis, the multiple time scale technique has been used to construct the extended Korteweg-de Vries (E-KdV) and modified Korteweg-de Vries (M-KdV) equations. They pinpoint the evolution of DADLs and solitary structures associated with dust acoustic (DA) mode, respectively. The relevant configurational parameters in our study include the superthermality of ions (kappa), obliqueness of propagation (theta), ion concentration (delta(i)), static magnetic field B-0 (via omega(cp); omega(cn)), and self-gravitational field (via gamma), as well as the density (mu(0)), charge (alpha), and mass (beta) ratio of positive to negative dust species. The proposed OPDP model permits positive and negative double layer polarities, while higher order nonlinear equation dictates us only positive polarity solitary structures. The main modification due to an increase in self-gravitational field (via gamma) is an enhancement in the spatial width of double layers, yet leaving their amplitude, phase speed, and polarity practically unaffected. With enhanced superthermality and other intrinsic parameters in OPDP model, there is an opposite trend in both amplitude and width of double layers, while the amplitude and the width of solitary waves (via M-KdV equation) undergo the identical behaviors. In particular, the amplitude of solitary waves manifests monotonic behavior for permissible range of obliqueness theta, whereas this scenario is acceptable to only width of double layers. The results are discussed in the context of laboratory and astrophysical plasma environments (e.g., cometary tails, Earth's mesosphere, etc.). Published by AIP Publishing.

• 出版日期2016-8