Sheath vs. quasi-neutral plasma voltages in high-pressure arc discharges

Abstract

Summary form only given. Two very different approaches to theoretical description of interaction of high-pressure arc plasmas with refractory cathodes exist in the literature. One group of researchers believes that space-charge effects on refractory cathodes are small and contribute to the arc voltage no more than one or two volts. Accordingly, these researchers use simulation models which are based on the assumption of quasi-neutrality, or even stronger assumption of local thermodynamic equilibrium (LTE), in the whole arc volume. Other researchers believe that the voltage drop in the near-cathode space-charge sheath is no less than 10V and rely on models where the near-cathode sheath plays a central role.