Sheath Formation in a Plasma with Regularized Kappa Distribution

TL;DR

This paper studies plasma sheath formation using a regularized kappa distribution, showing how superthermal effects influence electrostatic potential.

Contribution

The paper derives a modified Bohm criterion for plasma sheaths with regularized kappa distributed electrons.

Findings

The electrostatic potential variation is strongly influenced by the superthermal index κ and cutoff parameter α.

A plasma sheath with regularized kappa distribution exists when κ < 3/2.

The findings are relevant for plasma processing and Earth's inner magnetosphere studies.

Abstract

Debye shielding in an electron–ion plasma with regularized kappa distribution is examined. An unmagnetized collisionless plasma sheath with regularized kappa distributed electrons is investigated and the modified Bohm criterion is derived. It is found that the variation of the electrostatic potential depends significantly on the superthermal index κ and cutoff parameter α. If κ < 3/2, a plasma sheath with a regularized kappa distribution exists. Our present work may be useful in understanding plasma processing and plasma sheaths in related plasma regions (i.e., Earth’s inner magnetosphere).

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