Normalized spatio temporal plots of the (singlet + triplet) metastable source (a)–(c) and the electron impact excitation rate from the ground state into the He-I (3s)3S1 level (d)–(f), obtained from PIC/MCC simulations for different peak-to-peak voltage amplitudes, φpp (columns). The positions of the sheath edges are shown as solid white lines. The base frequency is = 13.56 MHz, N = 4, and the N_2 admixture concentration is 0.05%
Experimental data are marked as exp
Simulation data are marked as sim
x [t/TRf] , y[mm]
(Figure9a-9c): Sim Metastable source [a. u.]
(Figure9d-9f): Sim Exc. Rate [a. u.]
(Figure9a_9d_Sheath to Figure9c_9f_Sheath): Sim sheath edges of the plasma. These sheaths are the same for each corresponding metastable source and Exc. rate