Comparison of Propagation of a Shock Wave in a Decaying Plasma in Various Gases

The effect of gas humidity and composition oil shock wave splitting in the plasma of a decaying glow discharge is investigated in dried and moist air, nitrogen, and argon over various time periods after the discharge termination. The shapes of the signals reflecting the gas pressure distribution behind the shock wave in these media are approximately the same except for some values of decay time comparable to the characteristic time of decay of excited state concentration (including singlet oxygen) after the termination of the discharge (8 ms). The signals in the same four gases are compared quantitatively for different time periods after discharge termination by expanding the signal into a Fourier series. The free term and the second and third modes in the Fourier expansion are compared. Analysis is carried out for LIP to time periods of 60 ms.