MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade

Periodic edge localized modes (ELMs) are the non-linear consequences of pressure-gradient-driven ballooning modes and current-driven peeling modes becoming unstable in the pedestal region of high confinement fusion plasmas. In future tokamaks like ITER, large ELMs are foreseen to severely affect the...

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Authors: Meier, Lorenz, Hoelzl, Matthias, Cathey, Andres, Huijsmans, Guido, Viezzer, Eleonora, Dunne, Mike, van Dijk, Jan, Cruz Zabala, Diego José, Lackner, Karl, Günter, Sibylle
Format: article
Status:Published version
Publication Date:2023
Country:España
Institution:Universidad de Sevilla (US)
Repository:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/158688
Online Access:https://hdl.handle.net/11441/158688
https://doi.org/10.1088/1741-4326/acd5e2
Access Level:Open access
Keyword:Magnetic confinement fusion
Non-linear MHD
QH-mode
Tokamak plasmas
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spelling MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX UpgradeMeier, LorenzHoelzl, MatthiasCathey, AndresHuijsmans, GuidoViezzer, EleonoraDunne, Mikevan Dijk, JanCruz Zabala, Diego JoséLackner, KarlGünter, SibylleMagnetic confinement fusionNon-linear MHDQH-modeTokamak plasmasPeriodic edge localized modes (ELMs) are the non-linear consequences of pressure-gradient-driven ballooning modes and current-driven peeling modes becoming unstable in the pedestal region of high confinement fusion plasmas. In future tokamaks like ITER, large ELMs are foreseen to severely affect the lifetime of wall components as they transiently deposit large amounts of heat onto a narrow region at the divertor targets. Several strategies exist for avoidance, suppression, or mitigation of these instabilities, such as the naturally ELM-free quiescent H-mode (QH-mode). In the present article, an ASDEX Upgrade (AUG) equilibrium that features a QH-mode is investigated through non-linear extended magneto-hydrodynamic simulations covering the dynamics over tens of milliseconds. The equilibrium is close to the ideal peeling limit and non-linearly develops saturated modes at the edge of the plasma. A dominant toroidal mode number of n = 1 is found, for which the characteristic features of the edge harmonic oscillation are recovered. The saturated modes contribute to heat and particle transport preventing pedestal build-up to the ELM triggering threshold. The non-linear dynamics of the mode, in particular its interaction with the evolution of the edge safety factor, are studied, and suggest a possible new saturation mechanism for the QH-mode. The simulations show good qualitative and quantitative agreement with experiments in AUG. In particular, the processes leading to the termination of QH-mode above a density threshold are studied, which results in the transition into an ELM regime. In the vicinity of this threshold, limit cycle oscillations are observed.European Union 101052200European Union 805162Institute of Physics PublishingFísica Atómica, Molecular y NuclearEuropean Union (UE)European Union (UE). H20202023info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfapplication/pdfhttps://hdl.handle.net/11441/158688https://doi.org/10.1088/1741-4326/acd5e2reponame:idUS. Depósito de Investigación de la Universidad de Sevillainstname:Universidad de Sevilla (US)InglésNuclear Fusion, 63 (8), 086026.101052200805162https://doi.org/10.1088/1741-4326/acd5e2info:eu-repo/semantics/openAccessoai:idus.us.es:11441/1586882026-06-17T12:51:07Z
dc.title.none.fl_str_mv MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade
title MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade
spellingShingle MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade
Meier, Lorenz
Magnetic confinement fusion
Non-linear MHD
QH-mode
Tokamak plasmas
title_short MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade
title_full MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade
title_fullStr MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade
title_full_unstemmed MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade
title_sort MHD Simulations of Formation, Sustainment and Loss of Quiescent H-mode in the All-tungsten ASDEX Upgrade
dc.creator.none.fl_str_mv Meier, Lorenz
Hoelzl, Matthias
Cathey, Andres
Huijsmans, Guido
Viezzer, Eleonora
Dunne, Mike
van Dijk, Jan
Cruz Zabala, Diego José
Lackner, Karl
Günter, Sibylle
author Meier, Lorenz
author_facet Meier, Lorenz
Hoelzl, Matthias
Cathey, Andres
Huijsmans, Guido
Viezzer, Eleonora
Dunne, Mike
van Dijk, Jan
Cruz Zabala, Diego José
Lackner, Karl
Günter, Sibylle
author_role author
author2 Hoelzl, Matthias
Cathey, Andres
Huijsmans, Guido
Viezzer, Eleonora
Dunne, Mike
van Dijk, Jan
Cruz Zabala, Diego José
Lackner, Karl
Günter, Sibylle
author2_role author
author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Física Atómica, Molecular y Nuclear
European Union (UE)
European Union (UE). H2020
dc.subject.none.fl_str_mv Magnetic confinement fusion
Non-linear MHD
QH-mode
Tokamak plasmas
topic Magnetic confinement fusion
Non-linear MHD
QH-mode
Tokamak plasmas
description Periodic edge localized modes (ELMs) are the non-linear consequences of pressure-gradient-driven ballooning modes and current-driven peeling modes becoming unstable in the pedestal region of high confinement fusion plasmas. In future tokamaks like ITER, large ELMs are foreseen to severely affect the lifetime of wall components as they transiently deposit large amounts of heat onto a narrow region at the divertor targets. Several strategies exist for avoidance, suppression, or mitigation of these instabilities, such as the naturally ELM-free quiescent H-mode (QH-mode). In the present article, an ASDEX Upgrade (AUG) equilibrium that features a QH-mode is investigated through non-linear extended magneto-hydrodynamic simulations covering the dynamics over tens of milliseconds. The equilibrium is close to the ideal peeling limit and non-linearly develops saturated modes at the edge of the plasma. A dominant toroidal mode number of n = 1 is found, for which the characteristic features of the edge harmonic oscillation are recovered. The saturated modes contribute to heat and particle transport preventing pedestal build-up to the ELM triggering threshold. The non-linear dynamics of the mode, in particular its interaction with the evolution of the edge safety factor, are studied, and suggest a possible new saturation mechanism for the QH-mode. The simulations show good qualitative and quantitative agreement with experiments in AUG. In particular, the processes leading to the termination of QH-mode above a density threshold are studied, which results in the transition into an ELM regime. In the vicinity of this threshold, limit cycle oscillations are observed.
publishDate 2023
dc.date.none.fl_str_mv 2023
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/11441/158688
https://doi.org/10.1088/1741-4326/acd5e2
url https://hdl.handle.net/11441/158688
https://doi.org/10.1088/1741-4326/acd5e2
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Nuclear Fusion, 63 (8), 086026.
101052200
805162
https://doi.org/10.1088/1741-4326/acd5e2
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Institute of Physics Publishing
publisher.none.fl_str_mv Institute of Physics Publishing
dc.source.none.fl_str_mv reponame:idUS. Depósito de Investigación de la Universidad de Sevilla
instname:Universidad de Sevilla (US)
instname_str Universidad de Sevilla (US)
reponame_str idUS. Depósito de Investigación de la Universidad de Sevilla
collection idUS. Depósito de Investigación de la Universidad de Sevilla
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.300719

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