Path elimination of multi-burst streamer in normal air

Hong-Yu Chu^1*

¹Department of Physics, National Chung Cheng University, Chiayi, Taiwan

* Presenter:Hong-Yu Chu, email:phyhyc@ccu.edu.tw

We report the evolution of multi-burst filamentary streamer discharge generated by a Tesla coil power in normal air. The multi-burst discharges show self-similar pattern from successive branching discharge. The return stroke is also observed in the experiment with a floating electrode. Although the spatial size and the discharge current of the streamer discharge are much smaller than the ones in the lightning discharge, the growth dynamics of the multi-burst streamer discharge might shed light on the lightning-like discharge. The multi-burst streamers are generated by single electrode (a high voltage electrode only) and double electrodes (a high voltage electrode and a floating electrode) experimental setup. The trajectory of the streamer produced in the second wave packet follows the pathway of the streamer produced in the first wave packet with and without the floating electrode. The expanding speeds of the second burst streamers are found faster than the speeds of the first burst streamers. We show that the second (and the following) burst streamer propagates inside the hot gas channel generated by the first (and the previous) burst streamer. The rotational temperature of the hot gas channel generated by the streamer in the first wave packet was measured by optical spectrum method. It is suspected that there are rich amount of free electrons, ions and negatively charged molecules in the hot gas channel which is similar to the laser-guided streamer. By interrupting the hot gas channel, the presence of the hot gas channel is found to be crucial for the propagation of the following burst streamer. We also show that the length of floating electrode enhances the probability of streamer reaching the floating electrode.

Keywords: multi-burst streamer, Path elimination, lightning-like discharge