Effect of ambient gas species on microwave breakdown pattern

Abstract

The air, nitrogen, and helium breakdown caused by microwaves at atmospheric pressure are, respectively, investigated by solving the theoretical model, which consists of Maxwell’s equations and plasma fluid equations. The transport coefficients (e.g. an ionization frequency) are predicted by the Boltzmann equation solver BOLSIG+. The effective diffusion coefficient that describes properly the transition from the free diffusion to the ambipolar diffusion is introduced into the plasma fluid equations. The two-dimensional simulation results show that a filamentary plasma array is produced in the air and nitrogen breakdown, but it disappears completely in the helium breakdown. This is because the transport coefficients and wave scattering by the plasma differ from gas to gas. The simulated plasma patterns in the three different gases agree qualitatively with the experimental results. In addition, the plasma propagation speed in the nitrogen breakdown from the simulations is close to the experimental data.

Comparative analysis of single-surface multipactor discharges at different microwave frequencies

“…1) With the development of HPM technology to high peak power, long pulse and high repetition frequency, the multipactor discharge has become one of the great challenges facing the progress of HPM technology. [2][3][4][5][6][7] Therefore, the research on dielectric multipactor discharge is of great significance for related applications such as HPM systems and space communications.…”