Determination of the Gas Temperature in the Afterglow of Pulsed Discharges by Microwave Probing of Standing Acoustic Waves

摘要

The time‐varying gas temperature of afterglow plasmas is determined from the frequencies of standing acoustic waves which are produced during the breakdown of low‐pressure gases (0.1–20 Torr). The sound field is probed with free‐space microwave (9 and 70 Gc/sec) interferometers in transmission and reflection. Capacitor discharges are found to heat the gas significantly. The temperature does not decay to room temperature within the observed afterglow periods.