Physics of runaway electrons with shattered pellet injection at JET

JET Contributors

doi:10.1088/1361-6587/ac48bc

Physics of runaway electrons with shattered pellet injection at JET

JET Contributors

Fusion Energy Division

Research output: Contribution to journal › Article › peer-review

18 Scopus citations

Abstract

Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at the JET tokamak to investigate ways to prevent their generation or suppress them if avoidance is not sufficient. Avoidance is possible if the SPI contains a sufficiently low fraction of high-Z material, or if it is fired early in advance of a disruption prone to runaway generation. These results are consistent with previous similar findings obtained with Massive Gas Injection. Suppression of an already accelerated beam is not efficient using High-Z material, but deuterium leads to harmless terminations without heat loads. This effect is due to the combination of a large magnetohydrodynamic instability scattering REs on a large area and the absence of runaway regeneration during the subsequent current collapse thanks to the flushing of high-Z impurities from the runaway companion plasma. This effect also works in situations where the runaway beam moves upwards and undergoes scraping-off on the wall.

Original language	English
Article number	034002
Journal	Plasma Physics and Controlled Fusion
Volume	64
Issue number	3
DOIs	https://doi.org/10.1088/1361-6587/ac48bc
State	Published - Mar 2022

Funding

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under Grant Agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. The JET SPI project is a collaborative effort of EURATOM, the ITER Organization, and the US Department of Energy. It received funding from the ITER Organization. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, under Award No. DE-SC0020299.

Keywords

disruption
disruption mitigation
magnetohydrodynamics
plasma-wall interaction
runaway electrons
shattered pellet injection
tokamak

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1088/1361-6587/ac48bc

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@article{ef425749526540a4b994dae738909047,

title = "Physics of runaway electrons with shattered pellet injection at JET",

abstract = "Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at the JET tokamak to investigate ways to prevent their generation or suppress them if avoidance is not sufficient. Avoidance is possible if the SPI contains a sufficiently low fraction of high-Z material, or if it is fired early in advance of a disruption prone to runaway generation. These results are consistent with previous similar findings obtained with Massive Gas Injection. Suppression of an already accelerated beam is not efficient using High-Z material, but deuterium leads to harmless terminations without heat loads. This effect is due to the combination of a large magnetohydrodynamic instability scattering REs on a large area and the absence of runaway regeneration during the subsequent current collapse thanks to the flushing of high-Z impurities from the runaway companion plasma. This effect also works in situations where the runaway beam moves upwards and undergoes scraping-off on the wall.",

keywords = "disruption, disruption mitigation, magnetohydrodynamics, plasma-wall interaction, runaway electrons, shattered pellet injection, tokamak",

author = "{JET Contributors} and C. Reux and C. Paz-Soldan and N. Eidietis and M. Lehnen and P. Aleynikov and S. Silburn and V. Bandaru and O. Ficker and M. Hoelzl and Hollmann, {E. M.} and S. Jachmich and E. Joffrin and Lomas, {P. J.} and F. Rimini and L. Baylor and A. Bleasdale and L. Calacci and F. Causa and D. Carnevale and I. Coffey and D. Craven and {Dal Molin}, A. and {De La Luna}, E. and {De Tommasi}, G. and J. Garcia and T. Gebhart and L. Giacomelli and A. Huber and E. Khilkevich and C. Lowry and E. MacUsova and A. Manzanares and M. Nocente and E. Panontin and G. Papp and G. Pautasso and A. Peacock and V. Plyusnin and A. Shevelev and D. Shiraki and C. Sommariva and C. Sozzi and S. Sridhar and R. Sweeney and G. Szepesi and Tinguely, {R. A.} and J. Wilson",

note = "Publisher Copyright: {\textcopyright} 2022 IOP Publishing Ltd.",

year = "2022",

month = mar,

doi = "10.1088/1361-6587/ac48bc",

language = "English",

volume = "64",

journal = "Plasma Physics and Controlled Fusion",

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T1 - Physics of runaway electrons with shattered pellet injection at JET

AU - JET Contributors

AU - Reux, C.

AU - Paz-Soldan, C.

AU - Eidietis, N.

AU - Lehnen, M.

AU - Aleynikov, P.

AU - Silburn, S.

AU - Bandaru, V.

AU - Ficker, O.

AU - Hoelzl, M.

AU - Hollmann, E. M.

AU - Jachmich, S.

AU - Joffrin, E.

AU - Lomas, P. J.

AU - Rimini, F.

AU - Baylor, L.

AU - Bleasdale, A.

AU - Calacci, L.

AU - Causa, F.

AU - Carnevale, D.

AU - Coffey, I.

AU - Craven, D.

AU - Dal Molin, A.

AU - De La Luna, E.

AU - De Tommasi, G.

AU - Garcia, J.

AU - Gebhart, T.

AU - Giacomelli, L.

AU - Huber, A.

AU - Khilkevich, E.

AU - Lowry, C.

AU - MacUsova, E.

AU - Manzanares, A.

AU - Nocente, M.

AU - Panontin, E.

AU - Papp, G.

AU - Pautasso, G.

AU - Peacock, A.

AU - Plyusnin, V.

AU - Shevelev, A.

AU - Shiraki, D.

AU - Sommariva, C.

AU - Sozzi, C.

AU - Sridhar, S.

AU - Sweeney, R.

AU - Szepesi, G.

AU - Tinguely, R. A.

AU - Wilson, J.

PY - 2022/3

Y1 - 2022/3

N2 - Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at the JET tokamak to investigate ways to prevent their generation or suppress them if avoidance is not sufficient. Avoidance is possible if the SPI contains a sufficiently low fraction of high-Z material, or if it is fired early in advance of a disruption prone to runaway generation. These results are consistent with previous similar findings obtained with Massive Gas Injection. Suppression of an already accelerated beam is not efficient using High-Z material, but deuterium leads to harmless terminations without heat loads. This effect is due to the combination of a large magnetohydrodynamic instability scattering REs on a large area and the absence of runaway regeneration during the subsequent current collapse thanks to the flushing of high-Z impurities from the runaway companion plasma. This effect also works in situations where the runaway beam moves upwards and undergoes scraping-off on the wall.

AB - Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at the JET tokamak to investigate ways to prevent their generation or suppress them if avoidance is not sufficient. Avoidance is possible if the SPI contains a sufficiently low fraction of high-Z material, or if it is fired early in advance of a disruption prone to runaway generation. These results are consistent with previous similar findings obtained with Massive Gas Injection. Suppression of an already accelerated beam is not efficient using High-Z material, but deuterium leads to harmless terminations without heat loads. This effect is due to the combination of a large magnetohydrodynamic instability scattering REs on a large area and the absence of runaway regeneration during the subsequent current collapse thanks to the flushing of high-Z impurities from the runaway companion plasma. This effect also works in situations where the runaway beam moves upwards and undergoes scraping-off on the wall.

KW - disruption

KW - disruption mitigation

KW - magnetohydrodynamics

KW - plasma-wall interaction

KW - runaway electrons

KW - shattered pellet injection

KW - tokamak

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U2 - 10.1088/1361-6587/ac48bc

DO - 10.1088/1361-6587/ac48bc

M3 - Article

AN - SCOPUS:85125477003

SN - 0741-3335

VL - 64

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 3

M1 - 034002

ER -

Physics of runaway electrons with shattered pellet injection at JET

Abstract

Funding

Keywords

UN SDGs

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