Radiation Intensity Measurement in Simulated Martian Atmospheres on the Double Diaphragm Shock Tube

Absolute spectral radiance behind a strong shock wave in a mixture (70%CO2+30%N2) modeling Martian atmosphere has been experimentally measured using a conventional double-diaphragm shock tube. Optical measurements were conducted via ICCD camera, and He was used as a driven gas. Experiments have been conducted for two combinations of initial pressures and shock speeds: 5-6 km/s for 133 Pa, and 6,3-7,6 km/s for 40 Pa, respectively. The experiments were mainly focused on measurements of spectral range of 200-400 nm, and 400-850 nm. In spectral range of 200-400 nm radiation of CN, CO and NO molecules was observed at shock wave speeds of both types: 5-6 km/s and 6,3-7,6 km/s. C2 molecules emission observed in spectral range 450-570 nm takes place only at shock velocities higher than 6,3km/s. Atomic oxygen at the wavelength of 777 nm is observed only at velocities higher than 6 km/s.