Onset of Linear Instability in a Complex Plasma with Cairns Distributed Electrons

I Habumugisha,N Noreen,E Jurua,S K Anguma

doi:10.4236/ijaa.2016.61001

Abstract

A rigorous theoretical investigation of linear dust ion acoustic (DIA) solitary waves in an unmagnetized complex plasma consisting of ion and ion beam fluids, nonthermal electrons that are Cairns distributed and immobile dust particles were undertaken. It was found out that, for large beam speeds, three stable modes propagated as solitary waves in the beam plasma. These were the “Fast”, “Slow” and “Ion-acoustic” modes. For two stream instability to occur between ion and ion beam, it is shown that or when .

Highlights

In a complex plasma, ion beam can significantly affect the propagation charateristics of solitary waves [1]
Further theoretical analysis of the dispersion relation (Equation (11), revealed that, in the limiting case of fb = 0, dust ion acoustic (DIA) solitary waves propagated in the beam with a phase velocity Vp = ω k, given by
As the ion beam speed increased, (Figure 3(a)) the phase speed of both the F- and S-modes increased while the IAmode remained unchanged

Summary

Introduction

Ion beam can significantly affect the propagation charateristics of solitary waves [1]. It was shown that with a non-thermal electron population, the nature of ion sound solitary structures may change, and solitons with both positive and negative density pertubations can exist [4] It serves as a useful theoretical model for the family of such non-Maxiwellian or non-thermal space plasmas and it has been used by quite a number of authors, e.g., [6] [7]. For large values of α , the Gaussian form is deformed and the distribution function develops “wings”, becoming multi-peaked This may lead to beam instability and as a result, the Cairns distribution is not a good model for coherent non-linear structures such as solitary waves and double layers for higher values of α [5]. One can note that the prescence of non-thermally distributed electrons gives rise to changes in the structured nature of solitary waves [7]

Description of the Model

Derivation of the Dispersion Relation

Theoretical Analysis

Numerical Analysis

Conclusions