TEMPERATURE MEASUREMENTS IN SIMULATED MARS ATMOSPHERES BASED ON THE CN RADICAL EMISSION SPECTRUM

Temperature measurements behind the strong shock waves for simulated Martian atmosphere were presented in this paper. Based on the inherent molecular structure characteristics of the CN radicals, the energy level distribution, the transition frequency and Einstein spontaneous emission transition probability were systematically analyzed and numerically studied. Meanwhile, the FWHM of apparatus function was measured experimentally to be Lorentzian profile of value 0.154nm by using of a narrow line width diode laser. The dependence of the spectral structure on the rotational temperature and vibrational temperature were numerically analyzed in detailed. In shock-tube experiments, the emission of CN (B²Σ⁺→X²Σ⁺) system measurements were performed behind a strong shock wave in a CO₂-N₂ mixture with two di erent conditions of initial pressure and velocity. Rotational and vibrational temperatures behind the strong shock wave, and the radiation structure of the shock layer, including induction, relaxation and equilibrium processes were obtained through analysis of time gating optical emission spectra with nanosecond temporal resolution.