Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector

A fast-ion loss detector (FILD) was installed for the first time at the mega amp spherical tokamak—upgrade (MAST-U) spherical tokamak during its upgrade in 2021. A new CMOS camera was installed in the MAST-U FILD acquisition system to provide high spatial resolution (1.1 MPx) with an acquisition fre...

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Autores: Velarde, Lina, Rivero-Rodriguez, J.F., Galdón Quiroga, Joaquín, Williams, T., Rueda-Rueda, José, Cano Megías, Pilar, Chacartegui, Ricardo, García-Muñoz, M., Blackmore, S., McClements, K. G., Sanchís Sánchez, Lucía, Viezzer, Eleonora
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/383841
Acceso en línea:http://hdl.handle.net/10261/383841
https://api.elsevier.com/content/abstract/scopus_id/85219527932
Access Level:acceso abierto
Palabra clave:Fast-ion loss detector
Fast-ion losses
Spherical tokamaks
Velocity-space
ASCOT
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oai_identifier_str oai:digital.csic.es:10261/383841
network_acronym_str ES
network_name_str España
repository_id_str
dc.title.none.fl_str_mv Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector
title Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector
spellingShingle Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector
Velarde, Lina
Fast-ion loss detector
Fast-ion losses
Spherical tokamaks
Velocity-space
ASCOT
title_short Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector
title_full Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector
title_fullStr Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector
title_full_unstemmed Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector
title_sort Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detector
dc.creator.none.fl_str_mv Velarde, Lina
Rivero-Rodriguez, J.F.
Galdón Quiroga, Joaquín
Williams, T.
Rueda-Rueda, José
Cano Megías, Pilar
Chacartegui, Ricardo
García-Muñoz, M.
Blackmore, S.
McClements, K. G.
Sanchís Sánchez, Lucía
Viezzer, Eleonora
author Velarde, Lina
author_facet Velarde, Lina
Rivero-Rodriguez, J.F.
Galdón Quiroga, Joaquín
Williams, T.
Rueda-Rueda, José
Cano Megías, Pilar
Chacartegui, Ricardo
García-Muñoz, M.
Blackmore, S.
McClements, K. G.
Sanchís Sánchez, Lucía
Viezzer, Eleonora
author_role author
author2 Rivero-Rodriguez, J.F.
Galdón Quiroga, Joaquín
Williams, T.
Rueda-Rueda, José
Cano Megías, Pilar
Chacartegui, Ricardo
García-Muñoz, M.
Blackmore, S.
McClements, K. G.
Sanchís Sánchez, Lucía
Viezzer, Eleonora
author2_role author
author
author
author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv European Commission
Engineering and Physical Sciences Research Council (UK)
Junta de Andalucía
Velarde, Lina [0000-0002-3986-1583]
Rivero-Rodriguez, J.F. [0000-0001-5074-0267]
Galdón Quiroga, Joaquín [0000-0002-7415-1894]
Rueda-Rueda, José [0000-0002-4535-326X]
Cano Megías, Pilar [0000-0001-5182-6513]
García-Muñoz, M. [0000-0002-3241-502X]
McClements, K. G. [0000-0002-5162-509X]
Sanchís Sánchez, Lucía [0000-0001-8211-3356]
Viezzer, Eleonora [0000-0001-6419-6848]
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Fast-ion loss detector
Fast-ion losses
Spherical tokamaks
Velocity-space
ASCOT
topic Fast-ion loss detector
Fast-ion losses
Spherical tokamaks
Velocity-space
ASCOT
description A fast-ion loss detector (FILD) was installed for the first time at the mega amp spherical tokamak—upgrade (MAST-U) spherical tokamak during its upgrade in 2021. A new CMOS camera was installed in the MAST-U FILD acquisition system to provide high spatial resolution (1.1 MPx) with an acquisition frequency of up to 3.5 kHz. This camera has enabled the systematic analysis of the velocity-space of the fast-ion losses measured in MAST-U presented in this manuscript. The main parameters that determine the FILD measurement have been analysed to maximise the signal in the detector: the orbit-following code ASCOT predicts an inverse relation between the FILD signal and the probe’s relative distance to the separatrix. This prediction has been validated experimentally, enabling the measurement of fast-ion losses in the flat-top phase of the discharge; furthermore, ASCOT simulations show a big impact of the edge safety factor (q95) on the toroidal deposition of the prompt losses, indicating that the signal in the MAST-U FILD can be maximised by running scenarios with | q 95 | < 6 . This prediction was validated experimentally by a scan in the toroidal magnetic field. The experimental resolution of the MAST-U FILD has been evaluated for a typical MAST-U scenario with 750 kA plasma current. The results show that the diagnostic resolution is in the order of 0.5 to 1 degree in pitch angle, and of 1 to 3 cm in gyroradius in current scenarios. A systematic analysis of the velocity-space of the losses shows that the measured gyroradii of the prompt losses match those of the neutral beam injector injection energies within the resolution of the diagnostic. The experimentally measured pitch angles have been compared with ASCOT simulations, and it has been found that the agreement is better for scenarios heated with the on-axis beam, since this beam enables measurements of the magnetic field pitch angle. This analysis has been applied to a discharge where type-III ELM-induced fast-ion losses were measured, showing that the ELMs result in an increase in the FILD signal, and that the losses are coming from passing orbits.
publishDate 2025
dc.date.none.fl_str_mv 2025
2025
2025
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/383841
https://api.elsevier.com/content/abstract/scopus_id/85219527932
url http://hdl.handle.net/10261/383841
https://api.elsevier.com/content/abstract/scopus_id/85219527932
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/EC/H2020/805162
The underlying dataset has been published as supplementary material of the article in the publisher platform at DOI http://dx.doi.org/10.1088/1361-6587/ad9be4
http://dx.doi.org/10.1088/1361-6587/ad9be4
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv IOP Publishing
publisher.none.fl_str_mv IOP Publishing
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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spelling Velocity-space analysis of fast-ion losses measured in MAST-U using a high-speed camera in the FILD detectorVelarde, LinaRivero-Rodriguez, J.F.Galdón Quiroga, JoaquínWilliams, T.Rueda-Rueda, JoséCano Megías, PilarChacartegui, RicardoGarcía-Muñoz, M.Blackmore, S.McClements, K. G.Sanchís Sánchez, LucíaViezzer, EleonoraFast-ion loss detectorFast-ion lossesSpherical tokamaksVelocity-spaceASCOTA fast-ion loss detector (FILD) was installed for the first time at the mega amp spherical tokamak—upgrade (MAST-U) spherical tokamak during its upgrade in 2021. A new CMOS camera was installed in the MAST-U FILD acquisition system to provide high spatial resolution (1.1 MPx) with an acquisition frequency of up to 3.5 kHz. This camera has enabled the systematic analysis of the velocity-space of the fast-ion losses measured in MAST-U presented in this manuscript. The main parameters that determine the FILD measurement have been analysed to maximise the signal in the detector: the orbit-following code ASCOT predicts an inverse relation between the FILD signal and the probe’s relative distance to the separatrix. This prediction has been validated experimentally, enabling the measurement of fast-ion losses in the flat-top phase of the discharge; furthermore, ASCOT simulations show a big impact of the edge safety factor (q95) on the toroidal deposition of the prompt losses, indicating that the signal in the MAST-U FILD can be maximised by running scenarios with | q 95 | < 6 . This prediction was validated experimentally by a scan in the toroidal magnetic field. The experimental resolution of the MAST-U FILD has been evaluated for a typical MAST-U scenario with 750 kA plasma current. The results show that the diagnostic resolution is in the order of 0.5 to 1 degree in pitch angle, and of 1 to 3 cm in gyroradius in current scenarios. A systematic analysis of the velocity-space of the losses shows that the measured gyroradii of the prompt losses match those of the neutral beam injector injection energies within the resolution of the diagnostic. The experimentally measured pitch angles have been compared with ASCOT simulations, and it has been found that the agreement is better for scenarios heated with the on-axis beam, since this beam enables measurements of the magnetic field pitch angle. This analysis has been applied to a discharge where type-III ELM-induced fast-ion losses were measured, showing that the ELMs result in an increase in the FILD signal, and that the losses are coming from passing orbits.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 No. EP/W006839/1]. This research received funding from the Plan Andaluz de Investigación, Desarrollo e Innovación (PAIDI 2020, No. 003456/A02W), Consejería de Transformación Económica, Industria, Conocimiento y Universidades de la Junta de Andalucía. 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). J Galdon-Quiroga acknowledges support from the MSCA PF programme under Grant No. 101069021.Peer reviewedIOP PublishingEuropean CommissionEngineering and Physical Sciences Research Council (UK)Junta de AndalucíaVelarde, Lina [0000-0002-3986-1583]Rivero-Rodriguez, J.F. [0000-0001-5074-0267]Galdón Quiroga, Joaquín [0000-0002-7415-1894]Rueda-Rueda, José [0000-0002-4535-326X]Cano Megías, Pilar [0000-0001-5182-6513]García-Muñoz, M. [0000-0002-3241-502X]McClements, K. G. [0000-0002-5162-509X]Sanchís Sánchez, Lucía [0000-0001-8211-3356]Viezzer, Eleonora [0000-0001-6419-6848]Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202520252025info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://hdl.handle.net/10261/383841https://api.elsevier.com/content/abstract/scopus_id/85219527932reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/H2020/805162The underlying dataset has been published as supplementary material of the article in the publisher platform at DOI http://dx.doi.org/10.1088/1361-6587/ad9be4http://dx.doi.org/10.1088/1361-6587/ad9be4Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/3838412026-05-22T06:33:51Z
score 15.812429

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