Electron acoustic solitary waves in a plasma with nonthermal electrons featuring Tsallis distribution

Abstract

The problem of solitary electron acoustic (EA) wave propagation in a plasma with nonthermal hot electrons featuring the Tsallis distribution is addressed. A physically meaningful nonextensive nonthermal velocity distribution is outlined. It is shown that the effect of the nonthermal electron nonextensivity on EA waves can be quite important. Interestingly, we found that the phase speed of the linear EA mode increases as the entropic index q decreases. This enhancement is weak for q > 1, and significant for q < 1. For a given nonthermal state, the minimum value of the allowable Mach numbers is lowered as the nonextensive nature of the electrons becomes important. This critical limit is shifted towards higher values as the nonthermal character of the plasma is increased. Moreover, our plasma model supports rarefactive EA solitary waves the main quantities of which depend sensitively on q. This dependency (for q > 1) becomes less noticeable as the nonthermal parameter decreases. Nevertheless, decreasing α yields for q < 0 a different result, a trend which may be attributed to the functional form of the nonthermal nonextensive distribution. Our study (which is not aimed at putting the ad hoc Cairns distribution onto a more rigorous foundation) suggests that a background electron nonextensivity may influence the EA solitons. R. Amour · M. Tribeche ( )

Re-examining the Cairns-Tsallis model for ion acoustic solitons

“…Furthermore, C q,α is a constant of normalization, which is dependent on q and α, and is given explicitly by Refs. [33,34] as …”

“…[33,34], we shall in this work not consider values of q > 1, as this physical region is not consistent with our focus on a long-tailed distribution function associated with an excess of energetic particles and is physically irrelevant for our purposes.…”

“…Subsequently, Amour et al [34] applied this distribution to the study of electron acoustic solitary waves in plasmas with an enhanced superthermal component. In this paper, we revisit the analysis of Ref.…”

Investigation of electromagnetic soliton in the Cairns–Tsallis model for plasma

“…As it is mentioned, in our plasma model, the electrons distribution function of plasma obey the Cairns-Tsallis distribution function as follow [31,32] …”

“…Whereas such a two-parameter demonstration of the distribution function could be useful in fitting to a wider range of experimental plasmas. Subsequently, Amour et al [32] applied this distribution to the study of acoustic solitary. Motivated by these efforts to explain various phenomena in the presence of non-Maxwellian particles, we investigate the electromagnetic soliton in non-Maxwellian plasma.…”