Quantum tunneling-enhanced charging of nanoparticles in plasmas

TL;DR

This paper investigates how quantum tunneling influences electron charging of nanoparticles in plasmas, revealing its significance mainly for nano-sized grains in cold, ultracold plasma environments with specific electron energy distributions.

Contribution

It provides a detailed analysis of quantum tunneling effects on nanoparticle charging in plasmas, highlighting conditions where this effect is significant, especially for nano-sized grains in cold plasmas.

Findings

Quantum tunneling effect is negligible for micron-sized dust grains.

Quantum tunneling becomes significant for nano-sized grains in cold plasmas.

High-energy electron tails reduce the tunneling contribution.

Abstract

The role of quantum tunneling effect in the electron accretion current onto a negatively charged grain immersed in isotropic plasma is analyzed, within the quasiclassic approximation, for different plasma electron distribution functions, plasma parameters, and grain sizes. It is shown that this contribution can be small (negligible) for relatively large (micron-sized) dust grains in plasmas with electron temperatures of the order of a few eV, but becomes important for nano-sized dust grains (tens to hundreds nm in diameter) in cold and ultracold plasmas (electron temperatures ~ tens to hundreds of Kelvin), especially in plasmas with depleted high-energy "tails" in the electron energy distribution.