(a) Experimental data for the space- and time-averaged helium metastable density as a function of the peak-to-peak value of the driving voltage waveform. (b) Simulation result for the ratio of the space- and time-averaged electron impact excitation rate from the ground state into the He-I (3s)3S1 level and the space- and time-averaged helium metastable density as a function of the peak to-peak value of the driving voltage waveform, normalized by this ratio at a peak-to-peak voltage of 500 V. The base frequency is f_0 = 13.56 MHz and N = 4
Experimental data are marked as exp
Simulation data are marked as sim
[V]
(Figure10a): Sim of Space- and time-averaged helium metastable densities and electron impact excitation [cm^{-3}]
(Figure10b): Sim of Ratio of the normalized space- and time-averaged excitation rate and the helium metastable density [Norm. Exc. Rate / n]
(Figure10b_fit): fit for the normalized space- and time-averaged excitation rate and the helium metastable density [Norm. Exc. Rate / n]