Model Analysis of Self- and Laser-Triggered Electrical Breakdown of Liquid Water for Pulsed-Power Applications

• Published in: IEEE transactions on plasma science Vol. 34; no. 5; pp. 1680 - 1691
• Main Authors: Jun Qian, Joshi, R.P., Schoenbach, K.H., Woodworth, J.R., Sarkisov, G.S.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.10.2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Breakdown voltage; Breakdowns; Cathodes; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric breakdown and space-charge effects; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Discharge in liquids; Electric breakdown; Electric currents; Electric discharges; Electric fields; Electrical engineering. Electrical power engineering; Exact sciences and technology; Gas lasers; High voltage or high current generators; High-current and high-voltage technology: power systems; power transmission lines and cables (including superconducting cables); Impact ionization; Laser modes; Liquids; Microbubble; Optical pulses; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma; Plasma applications; Plasma simulation; polarity effect; Simulation; submicrosecond pulse; Various equipment and components; water breakdown; Water; Microbubble; Electric discharges; Liquid dielectric; Liquid dielectric spark gap; Breakdown voltage; Liquid discharge; water breakdown; Polar liquid; Ultrashort pulse; Streamer; Ionization; polarity effect; submicrosecond pulse; Laser plasma interaction; Sandia laboratories; Triggering; Pulsed power technology; ns range; Pulsed power switches
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/TPS.2006.876520

Electrical breakdown simulations for liquids, in response to a submicrosecond (~100-200 ns) voltage pulse, are carried out. It is shown that breakdown is initiated by field emission at the interface of preexisting microbubbles. Impact ionization within the microbubble gas then contributes to plasma development, with cathode injection having a delayed and secondary role. The model used in this paper adequately explains experimentally the observations of prebreakdown current fluctuations, streamer propagation and branching, as well as disparities in hold-off voltage and breakdown initiation times between the anode and the cathode polarities. It is demonstrated that polarity effects basically arise from the large mobility difference between electrons and ions. Breakdown is shown to occur either through the application of an overvoltage pulse, or be triggered by an external laser under electrical stress. With laser excitation, a string of point plasma formation is predicted, followed by rapidly propagating streamers and subsequent breakdown. This matches the recent work at Sandia National Laboratories