Experimental investigation of excitation of argon metastables by an electron swarm in argon nitrogen gas mixtures

Abstract

Excitation of argon metastable levels (43P2 +43Po) in a nonselfsustained discharge in Ar(>99%)+N2(<__l%) gas mixtures has been investigated by measuring N 2 second positive group which is the result of excitation transfer from Ar metastables to N 2 molecules. The method is based on the assumption, experimentally verified, that addition of small quantities of N 2 do not change markedly the probability of Ar excitation. The obtained excitation coefficients for production of Ar m in the E/N range (20-70) x 10 21 Vm 2 are (3.5-13) x 10 22 m 2 with an estimated uncertainty of -t-50 %. Simultaneously, excitation coefficients for direct excitation of nitrogen C-state by swarm electrons in Ar-N 2 mixtures have been obtained. A comparison of nitrogen spectra excited by electrons and by argon metastables showed significant differences in relative population of vibrational and rotational levels of the N2(CaH,) state in these two cases.

Modeling and diagnostics of the structure of rf glow discharges in Ar at 13.56 MHz

“…The ensemble average of electron energy in the bulk plasma under the conditions given in Eq. (13) is independently calculated at 5.3 eV by the direct numerical procedure using the Boltzmann equation [88]. In Table I, Torr.…”

“…1(b) and Eq. (13)] [76], since the bulk density of the electrons is temporally constant. The situation in A;(z, r) at 0.1 Torr is somewhat difFerent from 1.0 and 0.5 Fig.…”

“…Realistic models are possible because of the work devoted to measuring both the microscopic collision cross sections between the charged particle and Ar [4][5][6][7][8][9][10][11][12], and the macroscopic swarm parameters in Ar [4,[13][14][15][16][17][18][19][20][21][22][23][24]. Reliable radiative lifetimes and deactivation rate constants for the excited states in Ar have been also reported [25 -35].…”

Axial light emission and Ar metastable densities in a parallel plate dc microdischarge in the steady state and transient regimes

“…Nevertheless it is evident that losses are high and thus in selfpulsed operation the losses would be twice as high as in dc operation which would require a more efficient production of metastables in the pulse. As the excitation coefficient increases rapidly with E/n [38] and instantaneous E/n also overshoots (see figure 3) the steady-state values, the results indicate an increased effective production of metastables in the oscillating mode as compared with the steady-state conditions.…”

Measurements and analysis of excitation coefficients and secondary electron yields in Townsend dark discharges

“…Von Engel was the first to perform such experiments in the 1950s [1], but actually very few groups have measured excitation coefficients until today. The early studies also include the work of Nygaard [2], Teich [3], Urošević and co-workers [4] and Legler [5]. Most importantly, Phelps 1 Author to whom correspondence should be addressed.…”