Ion transport simulation in a low-pressure hydrogen gas at high electric fields by a convective-scheme method

A convective scheme 1D simulation was used to study the coupled transport of H + , H 2 + and H 3 + ions in an hydrogen gas for high E/N reduced electric fields. Results show that for a weakly dissociated gas, H 3 + ions are dominant for E/N values up to about 2 kTd. They indicate the existence of non-equilibrium energetic H 3 + ions and permit the limitations of fluid approaches for high field gradients to be shown. Results are of interest for plasma-material and plasma-cathode interactions in hydrogen discharges.