Multilayer-Structured Discharge in Plasma Ionization Breakdown near a Dielectric Surface

Abstract

Multipactor discharges are widely observed in rf accelerators, high power microwave transmission and space-based communication systems [1] - [2] . Understanding the fundamental physics of the transit multipactor and ionization breakdown is important. In this work, a novel multilayer-structured discharge (MSD) is reported in multipactor-coexisting plasma ionization breakdown by fully kinetic particle-in-cell (PIC) simulations [3] - [7] . The observed multilayer structure is originated by the response of ions to the electric field. It is found that the electron diffusion and multipactor discharge near the surface produce two electric fields in opposite directions towards and away from the dielectric surface, respectively. Thus, ions are gathered to form a locally high density profile, which is followed by the electron density. Furthermore, the relatively stronger restoring field induced by the multipactor discharge drives the ions away from the surface, and the locally high electron density diffuses away from the surface, resulting in a local electric field also away from the surface, which drives the ion density peak to propagate towards the bulk plasma. Such a process is periodically repeated, and finally, a MSD is formed, and propagate into bulk region.