Bistable Intrinsic Charge Fluctuations of a Dust Grain Subject to Secondary Electron Emission in a Plasma

TL;DR

This paper models charge fluctuations of a dust grain in plasma considering secondary electron emission, revealing bistability and metastability phenomena that depend on plasma conditions and charge states.

Contribution

It introduces a master equation approach to analyze intrinsic charge fluctuations, highlighting the conditions for bistability and metastability in plasma-dust interactions.

Findings

Charge fluctuations can be bistable with secondary electron emission.

Metastability allows charge state transitions between two stable macrostates.

Bistability depends on plasma distribution and secondary electron emission presence.

Abstract

A master equation was formulated to study intrinsic charge fluctuations of a grain in a plasma as ions and primary electrons are attached to the grain through collisional collection, and secondary electrons are emitted from the grain. Two different plasmas with Maxwellian and non-Maxwellian distributions were considered. The fluctuations could be bistable in either plasma when the secondary electron emission is present, as two stable macrostates, associated with two stable roots of the charge net current, may exist. Metastablity of fluctuations, manifested by the passage of the grain charge between two macrostates, was shown to be possible.