The development of a spatially uniform fast ionization wave in a large discharge volume

A high-voltage nanosecond breakdown in the form of a fast ionization wave (FIW) has been obtained and investigated in a large discharge volume (of 40 I). For various regimes in the air pressure range 10^-2-4 Torr the velocity of breakdown front propagation and energy absorption by the plasma were measured. A high level of spatial uniformity and reproducibility of the discharge was demonstrated. The possibility of propagation of FIWs in electrodeless systems was shown. It is demonstrated that the FIW propagates quasi-spherically in a free-boundary space until the reduced electric field in the wavefront is close to or exceeds the electron run-away threshold, otherwise the FIW loses its homogeneity and becomes transformed into a streamer corona discharge.