Measured normalized spatio-temporal plots of the emission of the 706.5 nm He I line (top row) and of the computed electron-impact excitation rate from the He I ground state into the He I (3s)3S1-state (bottom row). Results are shown for different driving voltage amplitudes (columns). The powered electrode is situated at x = 0, while the grounded electrode is located at x = 1 mm. Discharge conditions: 13.56 MHz, 1 slm He-flow, 2.5 sccm N2-flow. In the simulation the ion induced SEEC is set to 0.1, 0.3, and 0.2 for N+ 2 , He+, and He+ 2 ions, respectively, and the electron reflection probability at the electrodes is 50 %.
Experimental data are marked as exp
Simulation data are marked as sim
x [t/TRf] , y[mm]
(Figure5a-5c): exp Exc rate [a. u.] emission of 706.5nm line for 270V, 315V and 355V respectively
(Figure5d-5f): sim Exc. Rate [a. u.] electron-impact excitation rate from the He I ground state into the He I (3s)3 S1-state for 270V, 315V and 355V respectively