Assessment of the blast wave generated by a low-energy plasma igniter and spectroscopic measurements

Assessment of the output of plasma devices and comparison with thermodynamic calculations makes it possible to improve the efficiency of these devices. The experiment is based on two capacitor banks (1 and 20 kJ) and on a small plasma torch used in electrothermal-chemical (ETC) basic studies. The behavior of a plasma igniter is studied using spectroscopic measurements to obtain the electronic density from H/sub /spl alpha// line Stark width. The temperature is obtained from Boltzmann plots on copper and iron atomic lines. Under the local thermodynamic equilibrium assumption, the electron density (N/sub e/) depends on the electron temperature (T/sub e/) via Saha´s law (N/sub e//spl prop/T/sub e//sup 3/4/). A check on this behavior permits validation of the thermodynamic equilibrium assumption, and the pressure of the emitting area is obtained by using Dalton´s law. The flight time and the overpressure generated by the plasma igniter can be compared at the Sedov-Taylor blast wave theory. Finally, we give a comparison of the pressure of the emitting area found using Dalton´s law and also by applying the Sedov-Taylor blast wave model.