Multi-component dense plasma with ion and super-thermal electrons with kappa distribution

The soliton waves are one of the nonlinear phenomena which can propagate in the different types of plasma such as multiple particles of plasma, nonthermal plasma, and space plasma. Using the Sagdeev potential technique, the stability conditions of the soliton waves in the nonthermal plasma have been theoretically studied. One of the significant factors that can affect the propagation of the soliton waves is the distribution function such as nonMaxwellian distribution function or Kappa distribution function. In this paper, we try to investigate the soliton wave in the unmagnetized multi-component plasma consisting of the nonthermal electron and the nonthermal ion, positron and dust with Kappa distribution function. Then by using the Sagdeev potential, the nonlinear equation for the potential is obtained and then the compression and rarefaction soliton waves are computed with the numerical method for this nonlinear wave. Finally, by imposing the Sagdeev potential condition, we discuss the stability of these soliton waves.

Kappa Distributions: Statistical Physics and Thermodynamics of Space and Astrophysical Plasmas

Kappa distributions received impetus as they provide efficient modelling of the observed particle distributions in space and astrophysical plasmas throughout the heliosphere. This paper presents (i) the connection of kappa distributions with statistical mechanics, by maximizing the associated q-entropy under the constraints of the canonical ensemble within the framework of continuous description; (ii) the derivation of q-entropy from first principles that characterize space plasmas, the additivity of energy, and entropy; and (iii) the derivation of the characteristic first order differential equation, whose solution is the kappa distribution function.

Self-similar two-electron temperature plasma expansion into vacuum

A theoretical model is developed to describe self-similar plasma expansion into vacuum with two different electron temperature distribution functions. The cold electrons are modeled with a Maxwellian distribution while the hot ones are supposed to be non-thermal obeying a kappa distribution function. It is shown that ion density and velocity profiles depend only on cold electron distribution in early stage of expansion whereas ion acceleration is mainly governed by the hot electrons at the ion front and is strongly enhanced with the proportion of kappa distributed electrons. It is also found that when the kappa index is decreasing, the critical value of temperature ratio Teh/Tec, limiting the application of quasi-neutrality, becomes larger than the $5 + \sqrt {24} \approx 9.9$ value obtained in the two-electron Maxwellian Bezzerides model [Bezzerides, B., Forslund, D. W. & Lindman, E. L. (1978). Phys. Fluids21, 2179–2185].