Impact of q-dependent ionization frequency on sheath formation and behavior in magnetized collisionless plasma with non-extensive electron distribution

Abstract

This paper investigates the formation and structure of the sheath in a magnetized, collisionless, non-extensive plasma under the influence of electron impact ionization. A modified $q$-dependent electron-neutral ionization frequency is derived for the ionization process in the sheath region, revealing a strong dependence of the ionization frequency on the non-extensive parameter $q$. The results show that the ionization frequency significantly increases for lower values of $q$ (super-extensive electrons), leading to more energetic electrons and enhanced ionization effects. Additionally, a modified q-dependent Bohm criterion is derived, showing that the Bohm velocity limit for $q>1$ approaches the zero-source term limit. The impact of the $q$-dependent source term on sheath characteristics such as charged particle densities, space charge density, electric field, ion flux, and ion velocities is thoroughly examined. It is found that the source term affects the sheath characteristics, especially in the case of a super-extensive electron distribution ($q<1$) case. Furthermore, the analysis reveals that increasing the magnetic field angle leads to a stronger electric field within the sheath, and that the sheath length is significantly influenced by both the non-extensive parameter $q$ and the magnetic field angle.