Charging and heat collection by a positively charged dust grain in a plasma

TL;DR

This paper improves the understanding of how positively charged dust grains in plasma collect heat and charge, especially when electron emission affects their behavior, by refining existing theoretical models for better accuracy.

Contribution

It introduces a minimal modification to the OML$^+$ model, enhancing predictions of dust charge and heat flux in regimes where traditional theories fail.

Findings

OML$^+$ accurately predicts dust charge in positive regimes

Modified model improves heat collection flux estimates

Model works across various dust sizes and temperatures

Abstract

Dust particulates immersed in a quasineutral plasma can emit electrons in several important applications. Once electron emission becomes strong enough, the dust enters the positively charged regime where the conventional Orbital-Motion-Limited (OML) theory can break down due to potential well effects on trapped electrons. A minimal modification of the trapped-passing boundary approximation in the so-called OML$^+$ approach is shown to accurately predict the dust charge and heat collection flux for a wide range of dust size and temperature.