Measuring the gas temperature in a glow discharge in nitrogen with rapid pumping

Bands of the sequence &V = --2, --3, --4 of the second positive system of nitrogen N~(2+) were used in the capacity of the pyrometric component when studying glow discharge in sealed or weakly permeable tubes [6, 7]. The present work examines the usefulness of MURS for operational monitoring of the gas temperature in a glow discharge in an atmosphere of nitrogen with a pumping rate v through an interelectrode gap of ~i00 m/sec at an operating pressure of p > 1.33 kPa. The need for similar studies is caused by lasers being used in technology which have separate excitation of the gain medium's components [8] along with closed cycle CO2-EDL's. The merit of identifying the rotational temperature Tro t with the gas temperature Tg follows from the relationship between the rotational relaxation time TR-T [9-11] and the lifetime ~c of the C3Eu of nitrogen allowing for its deactivation due to collisions with other molecules [12]. For p = 1.33 kPa in correspondence with the data of [9-12], Tc/TR_T - i0, i.e., in the course of rc = 40 nsec rotational--translational relaxation does not take place and a Boltzmann distribution of the molecules is established in the CSHu state with respect to the rotational levels with a temperature Tro t = Tg. The validity of the proposition just made is demonstrated experimentally in [13].