Influence of liquid temperature on the characteristics of an atmospheric dc glow discharge using a liquid electrode with a miniature helium flow

Abstract

An atmospheric dc glow discharge using a liquid cathode and an axial miniature helium flow was generated stably between a nozzle anode and an electrolyte cathode (NaCl solution) in ambient air. Under low-current operation, the typical structure of dc glow discharges, i.e. a negative glow, a Faraday dark space and positive column, was observed. With increasing discharge current, the visible negative glow became weak and was replaced by an intense yellow-light emission, which was considered to originate from sodium atoms vaporized from the electrolyte surface by local heating due to ion bombardment from the glow discharge. To examine the effect of the liquid electrode temperature on the discharge characteristics, we controlled the electrolyte cathode temperature using an injection-type cooler or heater. The intensity of the sodium emission decreased when the electrolyte cathode was cooled, while it increased when the electrolyte cathode was heated. When a pulse-modulated dc voltage was applied, the sodium emission appeared with a delay relative to the inception of discharge, while nitrogen molecular lines appeared in the emission spectra and reached their peak intensities immediately. The temperature of the liquid cathode is an important factor in controlling the plasma-liquid interaction from the discharge and in resolving the detailed mechanism of the electrolyte cathode discharge.

Density distributions of OH, Na, water vapor, and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution

“…The plasma source used in this work was identical to that reported by Shirai and coworkers [19][20][21][22][23]. A dc power supply was connected between a stainless-steel gas nozzle and a platinum wire via a resister of 100 kΩ.…”

“…Among various methods for producing atmospheric-pressure plasmas in contact with liquids [7][8][9][10][11][12][13][14][15][16][17][18], in this work, we have employed dc glow discharge between a nozzle electrode and an electrolyte, which has been reported by Shirai and coworkers [19][20][21][22]. A reason for choosing this plasma source is that it can produce a stable positive column with a cathode sheath [23].…”

A review of plasma–liquid interactions for nanomaterial synthesis

“…The solution components can be forced into the plasma-liquid interface even into the bulk plasma by sputtering and/or evaporation [81][82][83], and this fact is usually ignored by researchers when considering the metal ion reduction by the PLIs. The solution components will take a form of droplet in the plasma-liquid interface and/or in the bulk plasma due to the transport by sputtering and/or evaporation.…”

Numerical Investigation of Electric Field in Gas Bubbles Surrounded with Conductive Liquid and Dielectric Material

“…Among them, various types of plasmas are used for these purposes, which include pulsed streamer discharges in water [1,4,5], dielectric barrier discharges [6][7][8], atmospheric dc glow discharges [9,10], low-pressure dc glow discharges [11,12], RF (13.56 MHz) discharges [13], arc discharges [14], and microwave discharges [15]. In our previous work, we have successfully obtained glow discharges in aqueous solution, which have been named as "solution plasmas", and applied this technique to nanoparticles synthesis and modification of the surface of nano-materials [16,17].…”