Effect of small additives of argon on the parameters of a non-uniform microwave discharge in hydrogen at reduced pressures

Abstract

Results of experiments and two-dimensional self-consistent simulation show that small (1–5%) additives of argon inserted in a hydrogen strongly non-uniform microwave discharge (electrode microwave discharge) reduce the emission intensity of excited particles, power absorbed in plasma, and electron and ion densities. Simulations have shown that this effect is linked with the reduction of the flux of ions to the electrode, which causes a decrease in the microwave field in plasma. These results illustrate the role of discharge non-uniformity in processes of discharge physics. It is shown that the argon admixture disturbs the discharge, and so the known method of optical actinometry cannot be used for plasma diagnostics in the case considered here. On the other hand, the addition of argon can be used to control plasma properties.