Modeling the low-pressure high-voltage branch of the Paschen curve for hydrogen and deuterium

Abstract: A physical and numerical model of the Townsend discharge in molecular hydrogen and deuterium has been developed to meet the needs of designing a plasma-based switching device for power grid application. The model allows to predict the low-pressure branch of the Paschen curve for applied voltage in the range of several hundred kiloVolts. In the regime of interest, electrons are in a runaway state and ionization by ions and fast neutrals sustains the discharge. It was essential to correctly account for both gas-phase and surface interactions (electron emission and electron back-scattering), especially in terms of their dependence on particle energy. The model yields results consistent with prior data obtained for lower voltage. The three-species (electrons, ions and fast neutrals) model successfully captures the essential physics of the process.