Normalized spatio-temporal plots of the electron impact excitation rate from the ground state into the He-I 1s3s 3S1 level (d-f), measured for different peakto-peak voltage amplitudes at N = 4 (“peaks”-waveforms) and z = −15 mm. The base frequency is f0 = 13.56 MHz and the O2 admixture concentration is 0.5%. The powered electrode is located at x = 0.
Experimental data are marked as exp
Calculated data are marked as calc
x [t/TRf], y[mm]
(Figure13a-13c): Exp Exc. Rate for O2-admixtures of 0.5% and N=4 with a peak-to-peak voltage of 350V, 450V and 550V respectively