Foundations of modelling of nonequilibrium low-temperature plasmas

Abstract

This work explains the need for plasma models, introduces arguments for choosing the type of model that better fits the purpose of each study, and presents the basics of the most common nonequilibrium low-temperature plasma models and the information available from each one, along with an extensive list of references for complementary in-depth reading. The paper presents the following models, organised according to the level of multi-dimensional description of the plasma: kinetic models, based on either a statistical particle-in-cell/Monte-Carlo approach or the solution to the Boltzmann equation (in the latter case, special focus is given to the description of the electron kinetics); multi-fluid models, based on the solution to the hydrodynamic equations; global (spatially-average) models, based on the solution to the particle and energy rate-balance equations for the main plasma species, usually including a very complete reaction chemistry; mesoscopic models for plasma-surface interaction, adopting either a deterministic approach or a stochastic dynamical Monte-Carlo approach. For each plasma model, the paper puts forward the physics context, introduces the fundamental equations, presents advantages and limitations, also from a numerical perspective, and illustrates its application with some examples. Whenever pertinent, the interconnection between models is also discussed, in view of multi-scale hybrid approaches.

Data Needs for Modeling Low-Temperature Non-Equilibrium Plasmas: The LXCat Project, History, Perspectives and a Tutorial

“…However, in many non-equilibrium LTPs, the electron and ion distribution functions are strongly non-Maxwellian due to the electric field and the collisions with the lowtemperature background gas. Therefore, rather than assuming a Maxwellian distribution function, it is often assumed that the distribution function in these plasmas is governed by local equilibrium between the acceleration by the electric field and the momentum and energy losses due to the collisions [25]. The distribution function then depends on the reduced electric field strength E/N (the ratio of electric field strength E to the gas density N), so that the transport coefficients and reaction rate coefficients can be expressed as functions of E/N.…”

Numerical Study of Jet–Target Interaction: Influence of Dielectric Permittivity on the Electric Field Experienced by the Target

“…The description of the electron energy in the model is obtained by implementing the electron energy conservation equation. By adopting the same approximations as in Alves et al [1] and Hagelaar and Pitchford [9], the equation is written:…”

Laser Ablation of Aluminum Near the Critical Regime: A Computational Gas-Dynamical Model with Temperature-Dependent Physical Parameters

“…In our work, the plasma-shielding effect is not also covered in the model, then the whole energy per unit area (Fluence, see Section 2.1 ) brought by the pulse reaches the target. If one aims to model the actual plume expansion, the starting point is to consider the plume as a low temperature plasma (LTP), as deeply reviewed in [ 23 ].…”