Role of Continuous Discharge Current for Secondary Streamer in Water
H. Fujita1, S. Kanazawa2, K. Ohtani1, A. Komiya1, T. Kaneko3, and T. Sato1
1Institute of Fluid Science, Tohoku University, Japan
2Department of Electrical and Electronic Engineering, Oita University, Japan
3Department of Electronic Engineering, Tohoku University, Japan
Abstract- A highly spatiotemporal analysis of underwater secondary streamers was conducted through precise measurements. The secondary streamers were visualized both as formed gas channels and as luminescence with an exposure time of 20 ns at 40 Mega-frames per second (Mfps), synchronized with the discharge current. A continuous component appeared on the current waveforms when secondary streamers propagated with a velocity of about 25 km/s with continuous light emission. The streamers slowed down and the luminescence became intermittent during the following pulsed currents. The amount of accumulated electrical charges estimated from the current waveform was proportional to the total streamer length. These results show that the appearance of a continuous component on the discharge current waveform characterizes secondary streamer propagation and that secondary streamer propagation could be identified by the monitoring of current waveforms without any visualization.
Keywords-Underwater discharge, secondary streamer, continuous discharge current, spatiotemporal analysis