Thomson scattering measurements of 100-kHz nanosecond repetitively pulsed discharges in argon and water vapor mixtures

摘要

In order to evaluate the effects of both gas composition and multiple pulses on nanosecond repetitively pulsed (NRP) discharges, spatially and temporally resolved measurements of plasma parameters in mixtures of argon and water vapor have been performed using laser Thomson scattering (LTS) and laser Rayleigh scattering (LRS). Bursts of 6-ns, 14-kV pulses at 100-kHz (10 pulses per burst operating at 30 Hz) are produced in a pin-to-sphere discharge geometry at a pressure of 80 Torr. Electron temperature T_e and electron number density n_e have been measured in the first microsecond between pulses. In addition, gas temperature T_g has been monitored by LRS over 10 microseconds between pulses. Selected pulses (i.e. 1st, 2nd, 5th, and 10th pulse) in a burst have been investigated, which reveal the difference and transition from single-shot pulsed discharge to NRP discharge regarding the plasma properties T_e, n_e in the discharge afterglow. The effect of water vapor on the discharge properties appears to vanish between the third and fifth pulse.