Plasmas sustained in bubbles in water: optical emission and excitation mechanisms

Controlling of reactive species in atmospheric Ar bubble discharge by adding N2/O2a

“…They claimed that for high N 2 content, the decrease is due to the quenching of OH with N 2 molecules, and for low N 2 concentration, this quenching effect is counterbalanced by a lesser recombination of OH + H radicals due to scavenging of H by N and N 2 , and hence OH emission becomes higher . In addition, the simulated results reported by Tian et al using two‐dimensional plasma hydrodynamics simulation show that the emission intensity of OH (A–X) with Ar bubble is higher than that with N 2 bubble under low voltage, while that is higher with N 2 bubble under high voltage . Thus it is reasonable that 1% N 2 added in Ar bubble discharge leads to the increase of OH (A–X), where the discharge power is found to be maximal in our experiment.…”

“…The discharge image of nanosecond pulsed pure Ar bubble discharge is shown in Figure (b). Commonly, the discharge starts at the tip of the powered electrode where the initial electrons are seeded . The maximum discharge strength can be observed near the hollow needle electrode, that is, discharge is brightest in this region.…”

“…The direct electron dissociative excitation of water molecules creates reactive species such as OH (R4), H (R5), and O (R6). Also, OH can be generated from the excitation collision of water molecules with metastable Ar atoms (R7) …”

Microwave Plasma Jet in Water: Characterization and Feasibility to Wastewater Treatment

“…An example of this method is the injection of gaseous bubbles into a liquid to facilitate the breakdown and increase the plasma volume [18,22,23]. The results obtained with this method are quite remarkable in terms of selectivity [18,[24][25][26], which increases the efficiency in removing specific pollutants; however, the plasma volume still remains too small to significantly increase the global efficiency of the processes.…”

Discharge phenomena in a cavitation bubble induced by liquid-phase laser ablation

“…However, just depositing the power into the liquid has difficulty in fundamental investigations on discharge mechanisms in bubbles, since the thermal production of bubbles occurs randomly. A bubble produced at a fixed position and a fixed timing is useful to carry out the efficient investigation on the discharge phenomena in a bubble [24][25][26][27].…”