Monte Carlo simulation of a microwave plasma in hydrogen

Abstract

Monte Carlo simulations of a microwave plasma (frequency 2.45 GHz, pressure 2-15 kPa) in hydrogen are reported. The simulation follows the chaotic motion of a number of electrons and ions under the influence of outer (microwave) and inner (other charge carriers) electric fields. The charge carriers collide with the neutral gas particles either in an elastic or inelastic manner. In such a simulation only basic physical laws have to be applied. The simulations produce reaction rates for the different reaction paths of main importance in a straightforward way. The electron energy distribution function (EEDF), which is simply a time average of the actual energies of the electrons, deviates from the Maxwell distribution by a depletion at low and high electron energies. Correction functions are derived which allow EEDFs under widely different plasma conditions to be calculated from the respective Maxwell distributions. Finally the results are applied to calculate mean mass densities in a closed plasma tube which are then compared with measured values.

Method of power density determination in microwave discharge, sustained in hydrogen–methane gas mixture

“…The model can be subdivided conventionally into the following modules: electrodynamic module (calculation of electromagnetic fields in the reactor using the FDTD method allowing for the plasma via conduction currents), plasma module (calculation of plasma density in the discharge), gas-dynamic module (calculation of the density, temperature, and velocity of the neutral gas), and the module of calculations of atomic-hydrogen density (on the basis of the balance equation allowing for diffusion and transition). The model was supplemented with the calculation of the electron energy distribution function by the Monte Carlo method [15]. When calculating the electron distribution function, we allowed for the influence of the gas temperature, oscillational excitation, and the degree of hydrogen dissociation.…”