Abstract

High-density short-gap sparks of nanosecond duration are triggered with a time jitter <1 nsec when charged up by a powerful 50-nsec, 7-kV pulse. This permits exact time coordination between the pulsed spark breakdown and a gated Kerr cell of 2–8 nsec exposure which is used for the photography of the initial channel. Development of the channel is observed by sequences of exposures at different gate settings. Maximum expansion velocities of 1.6 × 10⁶ cm/sec in 1-atm air are determined 2.6 nsec after zero time of the breakdown, of a 1.3-nHy nanolite which value is in agreement with earlier observations by Demidov. The expansion velocity appears to follow the current. Development of erosion clouds from the anode are observed and jetlike flares appear to form after the current has ceased.

© 1965 Optical Society of America

Electrode Phenomena in a High Current 20-Nanosecond Spark

Heinz Fischer and C. C. Gallagher
Appl. Opt. 6(12) 2176-2178 (1967)

Turbulent Eddies in High Density Spark Channels in Helium

Heinz Fischer and Karlheinz Schönbach
Appl. Opt. 7(2) 311-314 (1968)

Explosive Anode Erosion in High Current Sparks

K. Schönbach and H. Fischer
Appl. Opt. 9(7) 1695-1697 (1970)

Laser initiated spark development in an air gap

F. W. Lindner, W. Rudolph, G. Brumme, and Heinz Fischer
Appl. Opt. 14(9) 2225-2228 (1975)

Afterglow Tails and Stability of High-Density Nanosecond Arc Channels

Heinz Fischer and Walter B. Rüppel
Appl. Opt. 3(6) 769-772 (1964)