Two-dimensional simulations of gas discharge ignition in short gaps at voltage values below paschen minimum

Summary form only given. In this paper we theoretically investigate the breakdown formation process in discharge gaps where the pd parameter (product of a gap length and a working gas pressure) corresponds to the minimum point neighborhood of the static breakdown voltage curve.Different configurations of metallic electrodes and insulating elements compositions including various forms of dielectric coatings defects are received to study. In simulations the spatial plasma density and corresponding electric field distribution during development of gas discharge after its initiation by an external source of ionizing radiation or a low-temperature plasma flow were calculated in details. As a result of theoretical simulations the range of critical parameters (discharge gap geometry, shapes of electrodes, gas pressures, dielectric constants of the insulation, etc.) has been determined. They are likely to initiate possible breakdown under the influence of an external ionizing source or plasma flows. In particular, it was found that presence of dielectric structures with high emittance leads to significant decrease of the breakdown threshold voltage values that are lower than the Paschen´s curve minimum.