Transport and acceleration mechanism of fast ions during edge localized modes in ASDEX Upgrade

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openAccess

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Journal Title

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2023-08

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Mcode

Degree programme

Language

en

Pages

11
1-11

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Nuclear Fusion, Volume 63, issue 8

Abstract

Observations of enhanced fast-ion losses during edge localized modes (ELMs) have been reported in the ASDEX Upgrade tokamak, revealing losses above the injection energy. This suggests that fast ions can be accelerated and lost due to the ELMs. Recent analysis of the ELM-induced losses suggests that the fast ions are lost due to a resonant interaction with the electromagnetic perturbation during the ELM crash. The fast-ion transport and acceleration during ELMs is modelled using electromagnetic fields computed using the hybrid kinetic-MHD code MEGA, while fast-ion full orbits are tracked with the ASCOT code. Time-evolving 3D electromagnetic fields have been implemented in ASCOT to compute fast-ion orbits in the presence of fast MHD events such as ELMs. The simulations successfully reproduce a field-aligned pattern of the losses on the tokamak wall and the formation of an accelerated population in the lost fast-ion distribution, while they predict an accelerated population in the confined distribution. A parametric study of the fast-ion constants of motion suggests a resonant interaction between the fast-ions and the electromagnetic fields arising during the ELM crash. In the case of fast-ion acceleration, the perpendicular electric perturbation, with scales smaller than the fast-ion gyroradius, breaks magnetic moment conservation and resonantly modifies the fast-ion energy.

Description

Funding Information: This research received funding from the V Plan Propio de Investigación de la Universidad de Sevilla (PP2016-7145). Funding Information: This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 805162). Funding Information: This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200—EUROfusion) and from the EPSRC [Grant Number EP/W006839/1]. To obtain further information on the data and models underlying this paper please contact PublicationsManager@ukaea.uk . Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them. Funding Information: J. Galdon-Quiroga acknowledges support from the MSCA PF programme under Grant No. 101069021. Publisher Copyright: © 2023 Crown copyright, UKAEA.

Keywords

ELMs, fast-ions, fusion, MHD, Monte-Carlo, tokamak

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Citation

Rivero-Rodríguez, J F, Galdon-Quiroga, J, Domínguez-Palacios, J, García-Muñoz, M, Garcia-Vallejo, D, Gonzalez-Martin, J, McClements, K G, Sanchís, L, Särkimäki, K, Snicker, A, Todo, Y, Velarde, L, Viezzer, E & ASDEX Upgrade Team 2023, ' Transport and acceleration mechanism of fast ions during edge localized modes in ASDEX Upgrade ', Nuclear Fusion, vol. 63, no. 8, 086028, pp. 1-11 . https://doi.org/10.1088/1741-4326/ace2d3