Temperature measurement of initiation process of microsecond pulsed discharge in water by quantitative schlieren method

In the initiation process of microsecond pulsed discharge in water, Joule heating is believed to be responsible for the formation of a low-density region. Then, electron avalanche can be easily induced in this low-density region. The aim of this paper is to study the feasibility of the quantitative schlieren method in the temperature measurement of water in the initiation process of microsecond pulsed discharge. A lens-type schlieren system was applied in the measurement of the radial temperature around the tip of the electrode. Finite element analysis was used to simulate the electric field and temperature during the discharge. Measurement results of the schlieren quantitative schlieren method are compared with the simulation results of finite element analysis in terms of temperature and energy conversion. The comparison shows that most electrical energy is consumed in Joule heating of water in the initiation process of microsecond pulsed discharge. In the region with no thermal fluid, the temperature distributions obtained by the quantitative schlieren method and finite element analysis are in good agreement. This work is helpful in the quantitative study of the role of Joule heating in the initiation of the streamer in water.