Prebreakdown processes and electric fields in water with screened electrodes

Prebreakdown processes in water with modified electrodes were studied by optical and electrooptical methods. Nonelectrode and postbreakdown streamers are registered. Macroscopic and microscopic electric fields close to anode and cathode breakdown channel are measured. The conductivities of both streamers are estimated. Prebreakdown Kerr fringes in water were simulated by finite elements method. The comparison of simulation results with experimentally obtained data allows to estimate the macroscopic electric field and streamer conductivity. Macroscopic fields differ one from another: field close to cathode directed streamer has value 300 kV/cm, field close to anode directed streamer has value 2 MV/cm.