One-dimensional, multi-fluid model of the plasma wall transition. I. Hot electrons

Gyergyek, Tomaž (author), Kos, Leon (author), Costea, Stefan (author), Gyergyek, Miha (author), Kovačič, Jernej (author)

The plasma-wall transition in a plasma containing singly charged positive ions and two groups of electrons is studied with a one-dimensional steady-state multifluid model, which is presented in some detail. When the temperature and the initial density ratio between the two groups of electrons are varied, a transition between the two types of solutions to the model equations is observed. When the density and temperature of the hot electrons are above certain critical values, a high solution is observed. If the ion mass is decreased, these critical values increase. However, this effect only occurs with artificially small ion masses, which are significantly lower than the proton mass. In the high solution, the potential drop is determined by the hot electrons and is greater in absolute terms than in the low solution, where it is determined by the base electron population. The transition between the low and high solutions is very sharp if a neutrality condition is imposed. However, if the neutrality condition is replaced by the Poisson equation, the transition becomes blurred and the solutions exhibit oscillations. The temperature profiles of the ions are analyzed, and it is confirmed that the ion sound and the ion fluid velocity become equal at the breaking point of the plasma neutrality. It is shown how the ion source term, the initial ion velocity, and the initial electric field are found to be self-consistent. The density profiles of the negatively biased particles resulting from the fluid equations deviate very little those of from the Boltzmann-distributed particles, even if the corresponding source terms are quite large.

• Language: English
• Keywords: plasma, sheath, Bohm criterion, temeperature electron distribution
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering; FS - Faculty of Mechanical Engineering; FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: 22 str.
• Numbering: Vol. 14, iss. 4, [aricle no.] 045201
• PID: 20.500.12556/RUL-156109
• UDC: 533
• ISSN on article: 2158-3226
• DOI: 10.1063/5.0200376
• COBISS.SI-ID: 191198211
• Publication date in RUL: 08.05.2024

Record is a part of a journal

• Title: AIP advances
• Publisher: 2011-
• ISSN: 2158-3226
• COBISS.SI-ID: 24775975

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: plazma, plašč, Bohmov kriterij, dvotemperaturna elektronska porazdelitev

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0405
• Name: Fuzijske tehnologije

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0073
• Name: Reaktorska fizika