Plasma physics of liquids—A focused review

Abstract

The interaction of plasma with liquids has led to various established industrial implementations as well as promising applications, including high-voltage switching, chemical analysis, nanomaterial synthesis, and plasma medicine. Along with these numerous accomplishments, the physics of plasma in liquid or in contact with a liquid surface has emerged as a bipartite research field, for which we introduce here the term "plasma physics of liquids." Despite the intensive research investments during the recent decennia, this field is plagued by some controversies and gaps in knowledge, which might restrict further progress. The main difficulties in understanding revolve around the basic mechanisms of plasma initiation in the liquid phase and the electrical interactions at a plasma-liquid interface, which require an interdisciplinary approach. This review aims to provide the wide applied physics community with a general overview of the field, as well as the opportunities for interdisciplinary research on topics, such as nanobubbles and the floating water bridge, and involving the research domains of amorphous semiconductors, solid state physics, thermodynamics, material science, analytical chemistry, electrochemistry, and molecular dynamics simulations. In addition, we provoke awareness of experts in the field on yet underappreciated question marks. Accordingly, a strategy for future experimental and simulation work is proposed.

Cold atmospheric pressure plasmas in dermatology: Sources, reactive agents, and therapeutic effects

“…[ 137 ] The gas‐phase RONS intersected the water‐vapor saturated air over the liquid and are solvated afterward. [ 5 ] The photolysis of water by UV/VUV of CAP also contributed to the generation of radicals. Without alkane‐like hydrocarbons (RH aq , where “aq” denotes an aqueous species), O 2aq − , ONOO aq − , NO 3aq − , and H 3 O aq + dominated the water ions with H 3 O aq + determining the pH.…”

“…[137] The gas-phase RONS intersected the water-vapor saturated air over the liquid and are solvated afterward. [5] UV-visible spectroscopy (UV-Vis), [140,141] electron spin resonance (ESR), [73,142] and liquid chromatography-mass spectrometry (LC-MS) [143] are often used to measure the plasma-generated RONS in liquid. The half-life of RONS in liquid usually depends on pH, temperature, and other factors.…”

“…[4] The application of CAP in the field of medicine has been widely studied, such as decontamination and sterilization, cancer cell treatment, and skin disease treatment. [5][6][7][8][9][10][11] The sterilization effect of CAP has been employed to decontaminate heat-sensitive metallic or plastic surgical equipment. Several minutes of treatment by CAP can inactivate viruses and eliminate high concentrations of bacteria and spores.…”

High‐Performance Plasma‐Enabled Biorefining of Microalgae to Value‐Added Products

“…In the aforementioned examples, plasmas are usually generated in the gas phase and come into direct contact with the molecule that is being reformed or modified. However, to integrate plasmas into a process for direct liquefaction of biomass, in which reactions usually take place in a solvent, it may be more appropriate to generate plasmas by means of in‐liquid discharges . These types of discharges are considerably more complex, and usually, require higher energy inputs to ignite and sustain plasmas.…”

Direct comparison of high voltage breakdown measurements in liquid argon and liquid xenon

“…The weakest-link Weibull model provides an empirical explanation of the statistical origins of the area effect and is discussed in section 1.1. The physics of the initiation of dielectric breakdown and the succeeding discharge evolution within liquids remains an active subject of research [18]. Other than the electrode area, many other physical parameters have been observed to affect dielectric breakdown:…”