Leader effects on femtosecond-laser-filament-triggered discharges
- Electric Power Engineering Research Laboratory, Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan)
Dynamics of laser filaments in strong nonuniform electric fields is studied with high temporal and spatial resolution. Considerable reduction of the breakdown potential is found and is attributed to a filament-induced leader. Two breakdown modes, fast and slow, are found in 0.4 MV positive dc-voltage discharges activated by filaments that are induced by 65 fs, 170 mJ laser pulses. In the fast mode with duration order of a few microseconds, the filament may acquire the electrode potential and temporarily maintain it, becoming a leader. This gives rise to an average electric field over the attachment instability threshold between a leader head and cathode. Ionization waves precede the breakdown with maximal voltage reduction up to 40% for this mode. The slow mode with its duration order of 1 ms appears with a considerably smaller voltage reduction when the leader decays before the secondary streamer; the breakdown delay depends on negative and positive ion mobilities in this case.
- OSTI ID:
- 21069977
- Journal Information:
- Physics of Plasmas, Vol. 15, Issue 1; Other Information: DOI: 10.1063/1.2830647; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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