TY - JOUR
T1 - Electrical breakdown of water in microgaps
AU - Schoenbach, Karl
AU - Kolb, Juergen
AU - Xiao, Shu
AU - Katsuki, Sunao
AU - Minamitani, Yasushi
AU - Joshi, Ravindra
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2008/5/1
Y1 - 2008/5/1
N2 - Experimental and modeling studies on electrical breakdown in water in submillimeter gaps between pin and plane electrodes have been performed. Prebreakdown, breakdown and recovery of the water gaps were studied experimentally by using optical and electrical diagnostics with a temporal resolution on the order of one nanosecond. By using Mach-Zehnder interferometry, the electric field distribution in the prebreakdown phase was determined by means of the Kerr effect. Electric fields values in excess of the computed electric fields, which reach >4 MV cm-1 for applied electrical pulses of 20 ns duration, were recorded at the tip of the pin electrode, an effect which can be explained by a reduced permittivity of water at high electric fields. Breakdown of the gaps, streamer-to-arc transition, was recorded by means of high-speed electrical diagnostics, and through high-speed photography. It was shown, through simulations, that breakdown is initiated by field emission at the interface of preexisting microbubbles. Impact ionization within the micro-bubble's gas then contributes to plasma development. Experiments using pulse-probe methods and Schlieren diagnostics allowed us to follow the development of the disturbance caused by the breakdown over a time of more than milliseconds and to determine the recovery time of a water switch. In order to trigger water switches a trigger electrode with a triple point has been utilized. The results of this research have found application in the construction of compact pulse power generators for bioelectric applications.
AB - Experimental and modeling studies on electrical breakdown in water in submillimeter gaps between pin and plane electrodes have been performed. Prebreakdown, breakdown and recovery of the water gaps were studied experimentally by using optical and electrical diagnostics with a temporal resolution on the order of one nanosecond. By using Mach-Zehnder interferometry, the electric field distribution in the prebreakdown phase was determined by means of the Kerr effect. Electric fields values in excess of the computed electric fields, which reach >4 MV cm-1 for applied electrical pulses of 20 ns duration, were recorded at the tip of the pin electrode, an effect which can be explained by a reduced permittivity of water at high electric fields. Breakdown of the gaps, streamer-to-arc transition, was recorded by means of high-speed electrical diagnostics, and through high-speed photography. It was shown, through simulations, that breakdown is initiated by field emission at the interface of preexisting microbubbles. Impact ionization within the micro-bubble's gas then contributes to plasma development. Experiments using pulse-probe methods and Schlieren diagnostics allowed us to follow the development of the disturbance caused by the breakdown over a time of more than milliseconds and to determine the recovery time of a water switch. In order to trigger water switches a trigger electrode with a triple point has been utilized. The results of this research have found application in the construction of compact pulse power generators for bioelectric applications.
UR - http://www.scopus.com/inward/record.url?scp=43149126085&partnerID=8YFLogxK
U2 - 10.1088/0963-0252/17/2/024010
DO - 10.1088/0963-0252/17/2/024010
M3 - Article
AN - SCOPUS:43149126085
VL - 17
JO - Plasma Sources Science and Technology
JF - Plasma Sources Science and Technology
SN - 0963-0252
IS - 2
M1 - 024010
ER -