Ion temperature gradient mode and its solitons with regularized κ-distributed electrons

Abstract

The linear and the non-linear behaviors of the ion temperature gradient (ITG) mode in a plasma with regularized κ-distributed electrons are investigated using the fluid model. The dispersion relation of the ITG mode obtained on the basis of the local approximation shows that the growth rate of the ITG mode decreases with the increase in the spectral index κ and the exponential cut-off parameter α. It indicates that the presence of the superthermal electron leads to destabilization of the ITG mode, especially in the low κ ( κ < 1.5) region. In addition, the existence and the nature of the soliton structure driven by the ITG are studied using the pseudopotential technology. The soliton amplitude increases with the increase in the exponential cut-off parameter α and the spectral index κ, whereas the width of the soliton varies inversely. The present results will help to understand the low-frequency electrostatic wave and nonlinear structure in space and experimental plasmas with non-thermal electrons.

Small‐amplitude kinetic Alfvén solitons for hot electrons taking regularized kappa distribution in Earth's inner magnetosphere

“…This distribution is actually consistent with the hot electron distribution introduced in Reference [48], where the spectral index 𝜅 = 0.2 was employed to fit the observed hot electron distribution. The effects of the RKD on the properties of the ion acoustic soliton, [49,50] the dispersion of Langmuir wave, [51] the parallel electromagnetic modes, [52] and the ion temperature gradient mode [53] have been studied recently. Actually, the exponential cut-off of kappa distribution reduced the super luminal particles to the velocity momentum.…”