T. Fukuchi et al., STUDY OF ION HEATING AND COOLING IN A NITROGEN PLASMA BY LASER-INDUCED FLUORESCENCE, Journal of applied physics, 75(10), 1994, pp. 4906-4909
Laser-induced fluorescence from a low-pressure, magnetized, radio-freq
uency-generated plasma was observed for the first negative (1N) system
of N2+ (B2SIGMA(u)+ -X2SIGMA(g)+). A tunable dye laser was used to ex
cite the 1N system in the (0-0) and (0-1) transitions; individual rota
tional lines in the R branch were seen up to N=30, with the spin-slit
doublets resolved for N>16. Rotational ion temperature derived from th
e distribution of lines in the R branch is compared against translatio
nal temperature found from the linewidth. The heating of the plasma io
ns during the discharge and their cooling in the afterglow is observed
by both rotational and translational temperatures. Results show that,
for the present apparatus, the translational temperature is higher th
an the rotational temperature by a factor of approximately 10.