Experimental Study of a Fast Ionization Wave Discharge at High Pulse Repetition Rates*

The paper presents preliminary results of studies of fast ionization wave (FIW) discharges generated at high pulse repetition rates. The experiments were conducted in quiescent air in a 2 cm x 2 cm rectangular cross section discharge cell 20 cm long. The discharge cell can be modified to admit a 2 cm x 20 cm cross section flow transverse to the ionization wave propagation. The experiments demonstrated that the discharge produced by high-voltage, nanosecond pulse duration, high repetition rate pulse bursts develops as a series of repetitive fast ionization waves propagating across the entire discharge section, except at the conditions when plasma life time may considerably exceed time delay between two consecutive pulses. Wave speed and amplitude, as well as pulse energy coupled to the FIW discharge have been measured at pressures of 1 to 10 torr and pulse repetition rates of 1 to 100 kHz. The results also show that a dual polarity (+16 kV /-16 kV) FIW discharge at a pulse repetition rate of ν=10 kHz generates a uniform plasma in room air at pressures of up to P=20 torr, across distances of up to 20 cm. The results suggest that FIW discharges can be used for generating volume-filling, stable, nonequilibrium plasmas in high-speed gas flows