A 3D numerical study of positive streamers interacting with localized plasma regions

Abstract

Residual charged particles from previous discharges or external sources can produce some localized plasma regions, so called plasma patches in a discharge gap. Such plasma patches can affect the propagation morphology of passing streamers. Here we investigate how positive streamers interact with the plasma patches using a 3D PIC/MCC model. Simulations are performed in air with two planar electrodes, considering either an electron-ion or a purely positive ion plasma patch. When a positive streamer propagates through the electron-ion plasma patch, it shows a lower field enhancement, a weaker growth of electron density and a slower propagation velocity. If the plasma density in the patch is sufficiently high, it can even stop the propagation of streamer, however, streamer can restart from the other end of the patch after a while. In addition, the electron-ion plasma patch can change streamer's direction by electrostatic attraction or repulsion. If the plasma patch consists of purely positive ions, it can also slow down the propagation of streamer and change its direction by repulsion. In case of sufficiently high ion density, streamer's direction and velocity are strongly disturbed, resulting in splitting around the tip of the patch, the number of splitting channels increases with background electric field.

Streamer‐to‐precursor transition in N 2 –SF 6 mixtures under positive repetitive submicrosecond pulses

“…A 'detour' phenomenon, where the leader discharge tends to propagate along the periphery of residual positive ions region, was also observed by Hayakawa et al [28] under power frequency voltage in N 2 -C 2 F 6 mixture and by Seeger et al under pulsed DC voltage in SF 6 [29]. Under repetitive pulses, residual positive ions left by previous discharges may also impede the penetration of the second discharge into the first discharge region [19]. Although the second discharge is susceptible to triggering by residual negative ions, the discharge trajectory tends to deviate from the central axis.…”

“…under pulsed DC voltage in SF 6 [29]. Under repetitive pulses, residual positive ions left by previous discharges may also impede the penetration of the second discharge into the first discharge region [19]. Although the second discharge is susceptible to triggering by residual negative ions, the discharge trajectory tends to deviate from the central axis.…”

“…In addition, this abnormal experimental tendency may inspire one to reconsider the applicability of the uniform preionization initial condition in many previous simulations of repetitively pulsed discharge. Numerical simulations of 'double-pulse discharge' will be provided in future studies to verify qualitative explanations-for example, utilizing the localized plasma patch [19,23]. (4) A higher SF 6 concentration leads to increases in the number of applied pulses before breakdown and relative insulation capability.…”

“…The discharge following phenomenon, a common trend when one determines the breakdown voltage based on the up-and-down method, has been linked to the effects of residual negative ions, although the time interval is conventionally as long as several minutes [18]. Yuan et al simulated interactions between a positive streamer with electron-ion and purely positive ion plasma patches and found that propagation trajectory, electric field distribution, and electron density depended on the type and species density of plasma patches [19]. Streamer discharge is the dominant mechanism in a centimetre-scale N 2 and N 2 -O 2 mixture gap at a not extremely high gas pressure (e.g.…”

“…Yuan et al. simulated interactions between a positive streamer with electron‐ion and purely positive ion plasma patches and found that propagation trajectory, electric field distribution, and electron density depended on the type and species density of plasma patches [19]. Streamer discharge is the dominant mechanism in a centimetre‐scale N 2 and N 2 –O 2 mixture gap at a not extremely high gas pressure (e.g.…”