Electron swarm and streamer transport across the gas–liquid interface: a comparative fluid model study

Abstract

In this work we present a comparative study of fluid modeling methods in order to determine a recommended procedure to describe electron transport and streamer propagation across gasliquid interfacial regions. A test case of a cryogenic argon gas-liquid interface is simulated in this work to demonstrate applicability of the recommended procedures. The recommended nonlocal four moment model takes into consideration the density variation across the interface, and its associated impact on the transport properties/collisional transfer rates, as well as the spatial variation of the dielectric permittivity and the conduction band through the liquid binding energy, V 0 . The study examines the impacts of various assumptions involved in the modeling of electron transport across the plasma-liquid interface, by comparing a local field (drift-diffusion) approximation with the non-local (four moment) model, as well as a step function change in the density to actual spatially dependent density variations across the interface. We provide recommendations on necessary physical considerations needed to adequately model transport phenomena across gas-liquid interfaces.

‘Gas-dynamic diode’: Streamer interaction with sharp density gradients

“…These effects are difficult to study experimentally because a streamer discharge develops usually in the form of a number of filamentary channels (see, for instance, [1]). At present numerical calculations are widely used to simulate streamer development under various conditions (see, for instance, [16]). In particular, the influence of gas density gradients on streamer propagation was simulated for atmospheric high-altitude discharges [17,18] as well as for discharges that intersect bubbles and particles [19,20].…”

Simulating the Feasibility of Using Liquid Micro-Jets for Determining Electron–Liquid Scattering Cross-Sections

“…In addition to liquid dynamics, interfacial effects must be considered in the simulation of LµJs. A recent study investigated density-dependent inter-facial effects on electron transport [ 89 ]. Due to a change in de-localised electron energy across the interface, a density-dependent ( ), and hence spatially-dependent potential , exists, which produces an effective electric field .…”

“…A spatial density dependency was thus implemented within the MC simulation, along with the resulting potential, and hence electric field. In that study [ 89 ], it was found that a discrete change in density, and hence potential, did not significantly change the path and associated transport dynamics of such particles when compared to a realistic functional form, which in addition to computational considerations, motivated the use of a step function form for the change in density in the current work. Additionally, any variation in the potential resulting from the density change is left for future extensions of this work.…”

Electron transport and negative streamers in liquid xenon

“…It should also be noted that V 0 is implicitly included in the formula for the difference between the value of the ionization potential of an isolated atom and the value of the band gap in the liquid phase [40]. The inclusion of V 0 in calculations is necessary in the case of the gas-liquid interface (and other situations in which the number density of the background atoms is inhomogeneous) since the change of V 0 across the interface produces an effective electric field as shown in the recent study of Garland and co-workers [71]. Thus, in our calculations we can effectively represent discrete energy levels of quasi free electrons in the conduction band which have a minimum of V 0 with a continuous energy spectrum of free electrons which have a minimum of 0 eV.…”