Structure of positive streamers inside gaseous bubbles immersed in liquids

Abstract

Electric discharges and streamers in liquids typically proceed through vapour phase channels produced by the streamer or in gaseous bubbles. The bubbles can originate by enthalpy changes produced by the discharge or can be artificially injected into the liquid. Experiments on streamers in bubbles immersed in liquids have shown that the discharge propagates either along the surface of the bubble or through the volume of the bubble as in conventional streamer propagation in air. In this paper we report on results of a computational investigation of streamer propagation through bubbles immersed in liquids. We found that the dielectric constant of the liquid in large part determines the path the streamer takes. Streamers in bubbles immersed in a liquid with a high permittivity preferentially propagate along the surface of the bubble. Liquids with low permittivity can result in the streamer propagating along the axis of the bubble. The permittivity at which this transition occurs is a function of the applied voltage, size of the bubble and the conductivity of the liquid.

An adaptive Cartesian embedded boundary approach for fluid simulations of two- and three-dimensional low temperature plasma filaments in complex geometries

“…We observe a height-of-flight of the positive streamer above the surface and find that the sheath region l < 30 µm from the surface contains fewer electrons and is incompletely shielded by space and surface charge effects. The topological features that we observe is also observed in planar simulations by others [31,54,9,27,55,56], also with PIC codes [57], and the plasma sheath thickness that we observe is consistent with analytical estimations [55].…”

A review of plasma–liquid interactions for nanomaterial synthesis

“…The discharge process of plasma in bubbles is similar to that of glow discharge plasma in a gas phase and plasma over liquid since the bubbles consist of water vapor created by joule heating and electrolysis of water. The bubble plasma usually propagates along the plasma-liquid surface or cross the bubble without contacting the liquid surface depending on dielectric constants of the bubble gas and liquid [105,106]. While the streamer plasma in water is generated by decreasing of liquid density around the electrode by electric field enhancement [107] under a high overvoltage, or direct electron collision induced liquid water ionization under ultrahigh local electric field [108][109][110][111].…”

Decomposition of Acetic Acid Using Multiple Bubble Jets with Pulsed Electrical Discharge

“…The time 0 shows the start of recording pictures, and the exposure time was 20 ls for 50,000 frames/s. The streamer developed along the lower side of the hole slit in the side wall of the gas feeding tube and propagated along the bubble interface because of the surface charge [9]. The clear primary streamers were observed at 0, 1.020, and 2,960 ls in a growing bubble with a maximum diameter of 3 mm corresponding to 1,000 Hz.…”