Implementation of dressed cross-section model into the BIT1 code

0583705 - ÚFP 2024 RIV DE eng J - Článek v odborném periodiku
Tskhakaya, David
Implementation of dressed cross-section model into the BIT1 code.
European Physical Journal D. Roč. 77, č. 7 (2023), č. článku 135. ISSN 1434-6060. E-ISSN 1434-6079
Grant CEP: GA MŠMT(CZ) EF16_013/0001551; GA ČR(CZ) GA20-28161S
GRANT EU: European Commission(BE) 101052200
Institucionální podpora: RVO:61389021
Klíčová slova: BIT1 * DCSM * kinetic simulations
Obor OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)
Impakt faktor: 1.8, rok: 2022
Způsob publikování: Open access
https://link.springer.com/article/10.1140/epjd/s10053-023-00682-w

In the present work, we describe a new method, dressed cross-section model (DCSM), enabling implementation of large number of atomic transitions (~106 and more) in the kinetic simulations. The effective collision cross-sections derived from the DCSM show expected asymptotic behaviour: (i) For low plasma density, they reduce to the conventional cross-sections for single-step transitions from the ground state - (ii) the Maxwell-averaged rate coefficients are equal to the corresponding rate coefficients obtained from the Collisional-Radiative Model. We describe implementation of ionization and recombination DCSM into the PIC MC code BIT1 and present new results for tokamak plasma edge modelling. Graphical abstract: Realistic simulations of the plasma edge require precise treatment of plasma–impurity and plasma–neutral particle interactions. Full fluid, or fluid plasma—kinetic neutral models employ effective collision rates derived from the Collisional-Radiative Models (CRM) precalculated by different atomic data providers (e.g. see Summers and O’Mullane (AIP Conf. Proc. 1344:179, 2011)). These CRM incorporate large number of atomic states (103 and more) and corresponding transitions (~106), but assume Maxwellian energy distribution functions (EDF) for colliding particles. In order to describe processes in a non-Maxwellian plasma, kinetic models are applied. Such models operate with collision cross-sections and due to limited computing power of present-day computing facilities can simulate just a few dozens of interaction channels, see Tskhakaya (Plasma Phys Contr Fusion 59:114001, 2017), Mijin et al. (Comput Phys Commun 258:107600, 2021) and references there.[Figure not available: see fulltext.] The DCSM consists of two steps: calculation of averaged cross-sections for excitation collisions from the ground state and introduction of effective cross-sections based on CRM rate coefficients. The effective cross-sections derived from the DCSM show expected asymptotic behaviour: i. For low plasma density, they reduce to the direct transition cross-sections from the ground state - and ii. the Maxwell-averaged rate coefficients obtained from the DCSM are equal the corresponding CRM rate coefficients. We demonstrate application of the DCSM in simulations of the tokamak scrape-off layer.
Trvalý link: https://hdl.handle.net/11104/0351750