Electromagnetic particle-in-cell modeling of an electron cyclotron resonance plasma discharge in hydrogen

TL;DR

This paper presents a detailed electromagnetic particle-in-cell simulation of an electron cyclotron resonance hydrogen plasma, revealing kinetic effects, electron energy distributions, and hydrogen radical production, with implications for practical plasma applications.

Contribution

It introduces a fully electromagnetic PIC/Monte Carlo model that accurately captures kinetic effects and hydrogen radical dynamics, surpassing fluid models in predictive capability.

Findings

Simulation matches experimental electron density and temperature.

Electron energy distribution is tri-Maxwellian, aligning with measurements.

Hydrogen radical production is accurately predicted by the model.

Abstract

A low pressure discharge sustained in molecular hydrogen with help of the electron cyclotron resonance heating at a frequency of 2.45 GHz is simulated using a fully electromagnetic implicit charge- and energy-conserving particle-in-cell/Monte Carlo code. The simulations show a number of kinetic effects, and the results are in good agreement with various experimentally measured data such as electron density, electron temperature and degree of dissociation. The electron energy distribution shows a tri-Maxwellian form due to a number of different electron heating mechanisms, agreeing with the experimental data in the measured electron energy interval. The simulation results are also verified against a drift-diffusion model and proximity is observed between the computational results for the plasma density at the location of experimental measurement. However, the fluid approximation fails to accurately predict radical density and electron temperature because of the assumption of a single electron temperature. Special attention is paid to the characteristics of hydrogen radicals, whose production is strongly underestimated by the fluid model, whereas it is well predicted by the model considered here. The energy distribution of such radicals demonstrates the presence of a relatively large number of energetic hydrogen atoms produced by the dissociation of molecular hydrogen. The new insights are of significance for practical applications of hydrogen plasmas.