Tracking an individual streamer branch among others in a pulsed induced discharge

Abstract

The electro-dynamical properties and the mutual influence of several simultaneously propagating streamers are investigated in a point-to-plane configuration in air at atmospheric pressure under impulse voltage. When a fast and short high voltage pulse is applied to the point, a bunch of streamer branches develops into the interval. Since no previous ionized path has been traced before in the gap, streamers spread in the whole gap, branching while propagating. This behaviour is quite different from streamers under DC voltage conditions, which successively extend on the point–plane axis. The aim of this work is an attempt to distinguish the properties of an individual streamer simultaneously propagating with the others, by means of fast techniques based on simultaneous streak and still photographs and space-time decoupled currents measurements. Especially, their mean velocity can be estimated. In most cases, an axial streamer is observed, propagating faster than the others. This result can be interpreted in terms of the electric field space distribution by means of a three-dimensional electrostatic solver. This analysis shows that a mutual electro-dynamical influence is exerted from one streamer on another.

Spatiotemporally resolved imaging of streamer discharges in air generated in a wire-cylinder reactor with (sub)nanosecond voltage pulses

“…In the introduction we already mentioned that a higher applied voltage generally results in a higher streamer propagation velocity [2,5,6,9,3,11,4,47,12]. In the streamerlength discussion we showed that for the 2-m reactor the voltage is highest at the beginning and at the end of the reactor, so we would expect the highest streamer propagation velocities there.…”

“…The majority have used pointplate geometries which are very useful for fundamental streamer research because of optical accessibility and reproducibility [5,22,8,9,38,39,10,3,40,43,44,4,47]. Some used wire-plate geometries [6,7] and only a few have looked at coaxial geometries [2,12,11,52].…”

“…Streamer development 1.1.1. Streamer propagation velocity There are many studies on streamer development under pulsed voltage conditions [2,5,6,12,22,7,8,9,38,39,10,3,11,40,41,42,43,44,45,46,4,47,48]. For instance, several researchers have reported on streamer propagation velocities for a range of voltages and rise times.…”

“…This streamer propagation velocity is an important parameter for the streamer discharge in our coaxial reactor because it determines how far a streamer can propagate and therefore influences the distribution of the streamers in the plasma reactor. It is generally found and understood that a higher applied electric field increases the streamer propagation velocity and that the velocities are in the range of 10 5 -10 7 m·s −1 [2,5,6,9,3,11,4,47,12]. Furthermore, various experiments show that negative streamers generally have a lower propagation velocity than positive streamers [12,48,47,45,40,10,6], which is surprising because negative streamers propagate through electron drift and positive streamers propagate against the electron drift through photoionisation (and to a lesser extent background ionisation) [9,38,49].…”

Experimental setup for temporally and spatially resolved ICCD imaging of (sub)nanosecond streamer plasma

“…These streamers typically have a velocity in the range of 10 5 -10 7 m · s −1 and a diameter of several hundred micrometers to several millimeters. [5][6][7][8][9][10][11][12][13][14][15] Due to the high energetic electrons that are generated in these non-thermal plasmas, they are very efficient in producing highly reactive radical species. 16,17 These species can consequently react with, for instance, particles in gas streams (for example, pollutants, odor and dust), contamination in water, biological tissue, and material surfaces.…”