Effect of ion nonthermality on nonlinear dust acoustic wave propagation in a complex plasma in presence of secondary electron emission

Subrata Bhakta,Susmita Sarkar

doi:10.1063/1.4985747

Abstract

In this paper we have investigated the effect of ion nonthermality on nonlinear dust acoustic wave propagation in a complex plasma in presence of secondary electron emission considering equilibrium dust charge positive. In space and astrophysical plasmas presence of nonthermal ions have been detected by satellite observations. This ion nonthermality modifies propagation characteristics of dust acoustic waves when dust grains are charged by secondary electron emission mechanism. In case of dust charging by secondary electron emission process two stable equilibrium dust charge states exist out of which one is negative and the other is positive. Here we have considered positive equilibrium dust charge state and both adiabatic and nonadiabatic dust charge variation. Our investigation shows that characteristics of both dust acoustic soliton and dust acoustic shock depend on the strength of the ion nonthermality along with secondary electron yield. Increase in both ion nonthermality and secondary electron yield help to retain the shape of compressive dust acoustic soliton when dust charge variation is adiabatic and to maintain oscillation of the dust acoustic shock when dust charge variation is nonadiabatic.

Highlights

Wave propagation in dusty plasmas has become an important field of plasma research since early nineties of the last century. Both linear and nonlinear theories of dust acoustic and dust ion acoustic wave propagation have been extensively studied by several authors in different physical situation.[1,2]. In most of these studies dust grains were charged by plasma current, no electron emission from dust grains were considered
The negative equilibrium state exists for low value of the secondary electron yield whereas the positive equilibrium state exists for its high value
This figure show the existence of compressive dust acoustic soliton whose amplitude increases and width decreases with increasing δM i.e., with increasing secondary electron emission

Summary

INTRODUCTION

Wave propagation in dusty plasmas has become an important field of plasma research since early nineties of the last century. Linear theories of dust acoustic wave propagation in presence of secondary electron emission were studied earlier by considering both negatively and positively charged dust grains.[12,13,14,15,16] Since early nineties presence of non thermal ions in the study of wave propagation in dusty plasma were considered by several authors[17,18,19,20,21,22,23,24,25] but no one considered the presence of secondary electrons in their study.

FORMULATION OF THE PROBLEM

REDUCTIVE PERTURBATION ANALYSIS

NUMERICAL RESULTS

CONCLUSION