Optimal Composition of the Ar‒He Mixture of Atmospheric Pressure for Production of Metastable Argon Atoms in a Nanosecond Repetitively Pulsed Discharge

Abstract

Use is made of the 0D kinetic model to calculate the optimal composition of the Ar‒He mixture of atmospheric pressure in a nanosecond repetitively pulsed discharge (NRPD) generating excited argon atoms Ar* at an average density of ~10¹³ cm^–3 over the period. The optimal argon content is found, at which the minimum, reduced electric field amplitude E/N dependent on the NRPD parameters is required. In particular, the optimal argon content at plasma temperatures of 300 and 700 K is found to be ~0.3% and ~1%, respectively. The optimal argon content is practically independent of the pulse duration, pulse shape, interelectrode distance, and content of stray quenching impurities [up to ~(0.5–5) × 10^‒2 Torr of atmospheric gases]. Heat release in the discharge is calculated as a function of the composition of the Ar‒He mixture.