Spectroscopic measurement of plasma arc in nitrogen flow

In the present work is spectroscopiccally measured to obtain the vibrational and rotationnal temperature in arc heated flow of pure nitrogen. Arc heater experiments were conducted by using the Huels type arc heater at Aichi institute of technology. The B^2Σ_u^+-X^2Σ_g^+ transition of the N_2^+ molecule, is referred in the region of 383 to 392 nm as the N_2^+(lst negative) system. Spectra profiles in arc heated flow are obtained to estimate the vibrational temperature from the N_2^+(lst neg.) bands at the nearly stagnation point and at sonic throat. The vibrational temperature Tu are estimated to be about 10200K±1500K from inclination line (0, 0) to (1, 1), about 2340K±500K from (1, 1) to (2, 2), and about 3400K±500K from average inclination line close to (0, 0), (l, l), (2, 2), showing that the vibrational temperatures are not in equilibrium. The rotational temperature Tr is estimated to be about 1470K to 9870K from inclination line (0, 0) to (1, 1)in vibrational transition