CARS spectroscopy and optical interferometry of glow discharge plasma in nitrogen

The methods of spectroscopy of coherent anti-Stokes Raman scattering of light (CARS), optical interferometry, and emission spectroscopy are used to investigate the functions of distribution of nitrogen molecules over vibrational and rotational levels in the ground electron state. Also measured are the rate of gas heating and the distributions of gas and electron density and of translational temperature in the cross section of the discharge cuvette in plasma of dc glow discharge and contracted discharge. The obtained functions of distribution of nitrogen molecules over rotational and vibrational levels are well approximated by the Boltzmann and Treanor distributions, respectively. The radial dependence of the distribution of energy release in plasma of contracted discharge is suggested, and a solution is found of heat equation, which describes the distribution of translational temperature over the cuvette radius.