Gas temperature of capacitance spark discharge in air

Capacitance spark discharge has been widely used for studying the ignition of flammable gas caused by electrostatic discharge. In the present study, the gas temperature of capacitance spark discharge is measured. The gas temperature is an important factor in understanding the electrostatic ignition process because it influences the reaction rate of ignition. Spark discharge is generated in air with a pulse duration shorter than 100ns. The discharge energy is set to 0.03–1mJ. The rotational and vibrational temperatures of the N2 molecule are measured using the emission spectrum of the N2 second positive system. The rotational and vibrational temperatures are estimated to be 500 and 5000K, respectively, which are independent of the discharge energy. This result indicates that most of the electron energy is consumed in the excitation of vibrational levels of molecules rather than the heating of the gas. The gas temperature after discharge is also measured by laser-induced fluorescence of OH radicals. It is s...