[5a-A413-1~10] 8.2 Plasma measurements and diagnostics

[5a-A413-2] Spectroscopic Study on N₂ Molecule Puffed onto Expanding Argon Arc-Jet Plume

Senna Fukukawa¹, Atsushi Nezu^2,3, 〇Hiroshi Akatsuka^3,1 (1.Grad. Tokyo Tech., 2.TechDept, Tokyo Tech, 3.IIR, Tokyo Tech.)

Keywords:Nitrogen Gas Puff, Excited states of N2 Molecule, Argon Arc Plasma Plume

We analyzed the N₂ first positive (1PS) and the second positive (2PS) systems by optical emission spectroscopy (OES) when N₂ gas is puffed onto the Ar plasma jet. We found that T_v ~ T_r ~ 0.17 eV for C state, while T_v ~ 0.28 – 0.35 eV, T_r ~ 0.038 – 0.050 eV for B state, all of which are determined by fitting the calculated spectrum with those measured experimentally. Since the electron temperature in the observed area is about 0.4 eV, it is naturally considered that the N₂ C states are mainly produced by the resonant energy transfer from the Ar metastable to the N₂ ground state. It is also considered that similar values of T_v and T_r of the C state are the approximate value of the Ar gas temperature. Meanwhile, the vibrational distribution of the B state shows that the B state is populated not only by the radiative decay of the C state but also from other collisional processes, since the Franck-Condon principle cannot predict the vibrational population of the B state from the C state.