(a)-(c) Measured spatially resolved absolute densities of atomic oxygen obtained for different oxygen admixture concentrations. (d)-(f) peak and mean (spaceaveraged) values of the atomic oxygen density obtained from the measured space resolved data at fixed y = 0.5 mm and z = −15 mm. The columns show data for different numbers of consecutive driving harmonics, N. The base frequency is f0 = 13.56 MHz and the peak-to-peak value of the driving voltage waveform is kept constant at 500 V. The concentration of the O2 admixture is varied from 0.05 % to 1.0
Experimental data are marked as exp
Calculated data are marked as calc
(Figure7a-7c): Exp absolute densities of atomic oxygen for O2 admixtures varied from 0.05 % to 1.0% with N=1, N=2 and N=4 respectively
x [mm] , y[cm^-3]

(Figure7d-7f): Exp peak and mean (spaceaveraged) values of the atomic oxygen for N=1, N=2 and N=4 respectively
x [O2 add] , y[cm^-3]