Temperature Equilibration Due to Charge State Fluctuations in Dense Plasmas

TL;DR

This paper introduces a new mechanism for electron-ion energy transfer in dense plasmas, driven by charge state fluctuations, which could explain variations in plasma equilibration times observed experimentally.

Contribution

It develops a theoretical framework showing how charge state fluctuations mediate energy exchange, a novel process not previously characterized.

Findings

Charge state fluctuations can significantly contribute to energy transfer.

The energy exchange rate may be comparable to direct collisions.

The mechanism's dependence on plasma conditions could explain experimental variability.

Abstract

The charge states of ions in dense plasmas fluctuate due to collisional ionization and recombination. Here we show how, by modifying the ion interaction potential, these fluctuations can mediate energy exchange between the plasma electrons and ions. Moreover, we develop a theory for this novel electron-ion energy transfer mechanism. Calculations using a random walk approach for the fluctuations suggest that the energy exchange rate from charge state fluctuations could be comparable to direct electron-ion collisions. This mechanism is, however, predicted to exhibit a complex dependence on the temperature and ionization state of the plasma, which could contribute to our understanding of significant variation in experimental measurements of equilibration times.