Experiments on radiative cooling of a shock-heated gas

Overview & Synopsis

The paper describes shock-tube data on radiative cooling of an argon plasma, the electron density gradient, dne/dx, being a good indicator of the radiation lost by a shock-heated gas. The electron density profiles were obtained interferometrically with the use of an infrared light source (10.6 μ). The experimental results have shown that close to the end of the ionization relaxation zone, the measured electron densities and temperatures agree fairly well with the equilibrium calculations. This is an indication that the radiation yield has a weak effect in the relaxation zone and that the radiative losses in the equilibrium flow region should be taken into account. The measured losses are shown to be far in excess of those calculated for the continuum transparent throughout the whole spectral range, which is indicative of the discrete line radiation to be mainly responsible for the radiative losses.