Experimental research on surface wave Ar–He discharges at atmospheric pressure

The influence of He addition is studied in concentrations of up to 60% in an Ar surface wave discharge at atmospheric pressure and sustained with powers from 100 to 800 W. Although no He lines were detected, an increment in linear power density has been observed together with a decrease in both electron density and argon line intensities with the He proportion in the discharge. The influence of the He proportion on the radial contraction of the plasma is also presented. The results obtained reveal a change in the internal kinetics of the discharge with respect to a pure argon plasma, even at a low He concentration as low as 5%.