Estimations of the electric field strength of nonelectrode streamers in water

The electric field strength of a nonelectrode streamer in water has been estimated using data of electro-optical measurements. The microscopic field strength on the tips of the anode-directed and cathode-directed streamers is approximately $10$ MV/cm, while the macroscopic field strength of cathode-directed and anode-directed streamers near the streamer zone is approximately $300$ kV/cm and $2$ MV/cm, respectively.