Multispecies Particle Simulation of the Hydrogen Plasma Sheath Region

Abstract

A multispecies 1.5D PIC/MC model developed by our group is applied to plasma surface interaction. The model includes special variance reduction techniques for minority species and a modified null collision Monte Carlo method which gives the exact statistics of collision times also when including self-consistent fields. The model is applied to two test cases: capacitively coupled radio frequency discharge and plasma injection close to an absorbing wall. We discuss the kinetics of charged particles, the non equilibrium electron energy distribution function (eedf) and vibrational distribution function (vdf), the role of the gas temperature and the difficulties arising from the different time scales involved.

Observation of Bi‐Maxwellian Distributions in a H2 Plasma Produced by a Narrow Gap VHF Discharge

“…[9][10] An extreme condition of very narrow inter-electrode gap under very high pressure was assumed, which helps to reveal the variation trends of the plasma parameters. Here, the discharge gap d was 8 mm and the pressure was 133.3 Pa. A VHF voltage (60 MHz) was applied on the electrodes, where the amplitude V rf ¼ 100 V. The power in the simulation does not directly correspond to the experiment.…”

“…To understand the experimental results, we calculated the axial distribution of electron energy distribution function (EEDF) using the one‐dimensional PIC‐MCC code . An extreme condition of very narrow inter‐electrode gap under very high pressure was assumed, which helps to reveal the variation trends of the plasma parameters.…”

Low-pressure inductively coupled plasmas in hydrogen: impact of gas heating on the spatial distribution of atomic hydrogen and vibrationally excited states

“…2D fluid models have been used to study spatially resolved hydrogen plasmas in applications related to negative ion sources used in magnetic confined fusion [29][30][31][32][33][34], negative ion sources for particle accelerators [35,36], in the development of micro-discharges [37], and for surface processing [38]. 1D hybrid particle-in-cell models have also been developed to study the influence of atomic recombination on surfaces, the distribution of vibrational states within the plasma and velocity distributions of the negative ions [39][40][41][42][43][44][45]. Recently these 1D simulations have been used to study the advanced electrical plasma control strategies including voltage waveform tailoring plasmas [46], which demonstrated the importance vibrationally excited states [47].…”