The mechanism of precursor ionization ahead of strong shock waves has been studied in a low density shock tube. The experimental results are illustrated with Arrhenius plots with kink points dividing them into two par...The mechanism of precursor ionization ahead of strong shock waves has been studied in a low density shock tube. The experimental results are illustrated with Arrhenius plots with kink points dividing them into two parts with apparent activation energy ratio 1:2, namely with the values 7.7 eV and 15.3 eV, and varying with first and third power of the density respectively. A model is proposed to interpret the facts where the process taking place in the precursor region is a two step photo ionization accompanied with the drift flow effect of the gas relative to the shock wave or the ionization recombination effect according to whether the shock speed and initial density are low enough. The product of the A-A collision excitation cross section coefficient S* multiplied by the radiation cross section Q of Argon S×Q=1×10^(-36)(cm^4eV^(-1)) and the three body recombination coefficient of Argon at room temperature k_(ra)=1×10^(-24)(cm^(-6)s^(-1)).展开更多
基金The project supported by the National Natural Science Foundation of China
文摘The mechanism of precursor ionization ahead of strong shock waves has been studied in a low density shock tube. The experimental results are illustrated with Arrhenius plots with kink points dividing them into two parts with apparent activation energy ratio 1:2, namely with the values 7.7 eV and 15.3 eV, and varying with first and third power of the density respectively. A model is proposed to interpret the facts where the process taking place in the precursor region is a two step photo ionization accompanied with the drift flow effect of the gas relative to the shock wave or the ionization recombination effect according to whether the shock speed and initial density are low enough. The product of the A-A collision excitation cross section coefficient S* multiplied by the radiation cross section Q of Argon S×Q=1×10^(-36)(cm^4eV^(-1)) and the three body recombination coefficient of Argon at room temperature k_(ra)=1×10^(-24)(cm^(-6)s^(-1)).
