Sonoluminescence and collapse dynamics of multielectron bubbles in helium

TL;DR

This paper studies the collapse of multielectron bubbles in helium, revealing that their implosion dynamics resemble gas bubbles and can produce sonoluminescence through electron acceleration without gas heating.

Contribution

It introduces a detailed analysis of multielectron bubble collapse dynamics and demonstrates sonoluminescence driven by electron acceleration rather than gas ionization.

Findings

Collapse dynamics similar to gas bubbles

Electron acceleration causes sonoluminescence

Calculated radiation power spectrum

Abstract

Multielectron bubbles (MEBs) differ from gas-filled bubbles in that it is the Coulomb repulsion of a nanometer thin layer of electrons that forces the bubble open rather than the pressure of an enclosed gas. We analyze the implosion of MEBs subjected to a pressure step, and find that despite the difference in the underlying processes the collapse dynamics is similar to that of gas-filled bubbles. When the MEB collapses, the electrons inside it undergo strong accelerations, leading to the emission of radiation. This type of sonoluminescence does not involve heating and ionisation of any gas inside the bubble. We investigate the conditions necessary to obtain sonoluminescence from multielectron bubbles and calculate the power spectrum of the emitted radiation.