MHD spectroscopy of JET plasmas with pellets via Alfvén eigenmodes

Sergei E. Sharapov; H.J.C. Oliver; B.N. Breizman; M. Fitzgerald; L. Garzotti; Leena Aho-Mantila; Markus Airila; Antti Hakola; Aaro Järvinen; Juuso Karhunen; Seppo Koivuranta; Aki Lahtinen; Jari Likonen; Antti Salmi; Paula Sirén; Tuomas Tala; JET Contributors

doi:10.1088/1741-4326/aabb67

MHD spectroscopy of JET plasmas with pellets via Alfvén eigenmodes

Sergei E. Sharapov^*
, H.J.C. Oliver
, B.N. Breizman
, M. Fitzgerald
, L. Garzotti
, Leena Aho-Mantila
, Markus Airila
, Antti Hakola
, Aaro Järvinen
, Juuso Karhunen
, Seppo Koivuranta
, Aki Lahtinen
, Jari Likonen
, Antti Salmi
, Paula Sirén
, Tuomas Tala
, JET Contributors

^*Corresponding author for this work

Culham Science Centre
The University of Texas at Dallas
Forschungszentrum Jülich GmbH (FZJ)
Institute for Plasma Research
Universidade de Lisboa
Queen's University Belfast
University of Helsinki
Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA)
National Institutes for Quantum Science and Technology (QST)
University of Naples Federico II
National University of Distance Education
National Research Council (CNR)
ITER Organization
Petersburg Nuclear Physics Institute
Parthenope University of Naples
National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA)
Troitsk Institute for Innovation and Fusion Research
Uppsala University
National Institute for Cryogenics and Isotopic Technology
Max-Planck-Institut für Plasmaphysik (IPP)
Aalto University
Seoul National University
Institute of Plasma Physics (ASIPP CAS)
Chalmers University of Technology

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

8 Citations (Scopus)

Abstract

Alfvén eigenmodes (AEs) are routinely seen in present-day tokamaks and stellarators with energetic particles and they represent an attractive form of MHD spectroscopy that provides valuable information on background plasma and on the energetic particles. Possible use of AEs is assessed for MHD spectroscopy of plasma with high-velocity pellet injection employed for fuelling the plasma core. Diagnostics of temporal evolution of the ablated pellets, as well as physics effects determining the diffusion/relaxation of the post pellet profile are of high importance for validating the pellet models and extrapolating them towards ITER. In this paper, JET discharges with ICRH-driven AEs and pellets launched from outboard and inboard tracks are considered. During the pellet injection, an increase in plasma density on a time scale ≪ 50 ms occurs, and several effects on AEs are observed: (1) frequency of the AEs throughout the pellet injection sweeps down by as much as ∼30%, (2) the AE amplitudes increase during the AE frequency sweeping, and (3) spectrum of toroidal mode numbers of the AEs broadens significantly after the pellet injection. The effects observed are interpreted in terms of a rise in plasma density and an enhancement of the mode amplitude resulting from the resonance sweeping during the pellet injection.

Original language	English
Article number	082008
Journal	Nuclear Fusion
Volume	58
Issue number	8
DOIs	https://doi.org/10.1088/1741-4326/aabb67
Publication status	Published - 29 Jun 2018
MoE publication type	A1 Journal article-refereed

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 under grant agreement No 633053 and from the RCUK Energy Programme (grant number EP/P012450/1).

UN SDGs

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

SDG 7 Affordable and Clean Energy

Keywords

Alfven
frequency sweeping
fusion
MHD
subcritical
tokamak

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10.1088/1741-4326/aabb67

Cite this

Sharapov, S. E., Oliver, H. J. C., Breizman, B. N., Fitzgerald, M., Garzotti, L., Aho-Mantila, L., Airila, M., Hakola, A., Järvinen, A., Karhunen, J., Koivuranta, S., Lahtinen, A., Likonen, J., Salmi, A., Sirén, P., Tala, T., & JET Contributors (2018). MHD spectroscopy of JET plasmas with pellets via Alfvén eigenmodes. Nuclear Fusion, 58(8), Article 082008. https://doi.org/10.1088/1741-4326/aabb67

@article{6f4d297484bc4e71bced9d9611ff6080,

title = "MHD spectroscopy of JET plasmas with pellets via Alfv{\'e}n eigenmodes",

abstract = "Alfv{\'e}n eigenmodes (AEs) are routinely seen in present-day tokamaks and stellarators with energetic particles and they represent an attractive form of MHD spectroscopy that provides valuable information on background plasma and on the energetic particles. Possible use of AEs is assessed for MHD spectroscopy of plasma with high-velocity pellet injection employed for fuelling the plasma core. Diagnostics of temporal evolution of the ablated pellets, as well as physics effects determining the diffusion/relaxation of the post pellet profile are of high importance for validating the pellet models and extrapolating them towards ITER. In this paper, JET discharges with ICRH-driven AEs and pellets launched from outboard and inboard tracks are considered. During the pellet injection, an increase in plasma density on a time scale ≪ 50 ms occurs, and several effects on AEs are observed: (1) frequency of the AEs throughout the pellet injection sweeps down by as much as ∼30\%, (2) the AE amplitudes increase during the AE frequency sweeping, and (3) spectrum of toroidal mode numbers of the AEs broadens significantly after the pellet injection. The effects observed are interpreted in terms of a rise in plasma density and an enhancement of the mode amplitude resulting from the resonance sweeping during the pellet injection.",

keywords = "Alfven, frequency sweeping, fusion, MHD, subcritical, tokamak",

author = "Sharapov, \{Sergei E.\} and H.J.C. Oliver and B.N. Breizman and M. Fitzgerald and L. Garzotti and X. Litaudon and S. Abduallev and M. Abhangi and P. Abreu and M. Afzal and Aggarwal, \{K. M.\} and T. Ahlgren and Ahn, \{J. H.\} and Leena Aho-Mantila and N. Aiba and Markus Airila and R. Albanese and V. Aldred and D. Alegre and E. Alessi and P. Aleynikov and A. Alfier and A. Alkseev and M. Allinson and B. Alper and E. Alves and G. Ambrosino and R. Ambrosino and L. Amicucci and V. Amosov and Sund{\'e}n, \{E. Andersson\} and M. Angelone and M. Anghel and C. Angioni and L. Appel and Antti Hakola and Aaro J{\"a}rvinen and Juuso Karhunen and H.T. Kim and H.S. Kim and Seppo Koivuranta and Aki Lahtinen and Jari Likonen and Y. Liu and T. Makkonen and H. Nordman and Antti Salmi and M.I.K. Santala and Paula Sir{\'e}n and Tuomas Tala and \{JET Contributors\}",

note = "Publisher Copyright: {\textcopyright} EURATOM 2018.",

year = "2018",

month = jun,

day = "29",

doi = "10.1088/1741-4326/aabb67",

language = "English",

volume = "58",

journal = "Nuclear Fusion",

issn = "0029-5515",

publisher = "Institute of Physics IOP",

number = "8",

}

Sharapov, SE, Oliver, HJC, Breizman, BN, Fitzgerald, M, Garzotti, L, Aho-Mantila, L , Airila, M , Hakola, A , Järvinen, A , Karhunen, J, Koivuranta, S, Lahtinen, A, Likonen, J , Salmi, A, Sirén, P, Tala, T & JET Contributors 2018, 'MHD spectroscopy of JET plasmas with pellets via Alfvén eigenmodes', Nuclear Fusion, vol. 58, no. 8, 082008. https://doi.org/10.1088/1741-4326/aabb67

TY - JOUR

T1 - MHD spectroscopy of JET plasmas with pellets via Alfvén eigenmodes

AU - Sharapov, Sergei E.

AU - Oliver, H.J.C.

AU - Breizman, B.N.

AU - Fitzgerald, M.

AU - Garzotti, L.

AU - Litaudon, X.

AU - Abduallev, S.

AU - Abhangi, M.

AU - Abreu, P.

AU - Afzal, M.

AU - Aggarwal, K. M.

AU - Ahlgren, T.

AU - Ahn, J. H.

AU - Aho-Mantila, Leena

AU - Aiba, N.

AU - Airila, Markus

AU - Albanese, R.

AU - Aldred, V.

AU - Alegre, D.

AU - Alessi, E.

AU - Aleynikov, P.

AU - Alfier, A.

AU - Alkseev, A.

AU - Allinson, M.

AU - Alper, B.

AU - Alves, E.

AU - Ambrosino, G.

AU - Ambrosino, R.

AU - Amicucci, L.

AU - Amosov, V.

AU - Sundén, E. Andersson

AU - Angelone, M.

AU - Anghel, M.

AU - Angioni, C.

AU - Appel, L.

AU - Hakola, Antti

AU - Järvinen, Aaro

AU - Karhunen, Juuso

AU - Kim, H.T.

AU - Kim, H.S.

AU - Koivuranta, Seppo

AU - Lahtinen, Aki

AU - Likonen, Jari

AU - Liu, Y.

AU - Makkonen, T.

AU - Nordman, H.

AU - Salmi, Antti

AU - Santala, M.I.K.

AU - Sirén, Paula

AU - Tala, Tuomas

AU - JET Contributors

PY - 2018/6/29

Y1 - 2018/6/29

N2 - Alfvén eigenmodes (AEs) are routinely seen in present-day tokamaks and stellarators with energetic particles and they represent an attractive form of MHD spectroscopy that provides valuable information on background plasma and on the energetic particles. Possible use of AEs is assessed for MHD spectroscopy of plasma with high-velocity pellet injection employed for fuelling the plasma core. Diagnostics of temporal evolution of the ablated pellets, as well as physics effects determining the diffusion/relaxation of the post pellet profile are of high importance for validating the pellet models and extrapolating them towards ITER. In this paper, JET discharges with ICRH-driven AEs and pellets launched from outboard and inboard tracks are considered. During the pellet injection, an increase in plasma density on a time scale ≪ 50 ms occurs, and several effects on AEs are observed: (1) frequency of the AEs throughout the pellet injection sweeps down by as much as ∼30%, (2) the AE amplitudes increase during the AE frequency sweeping, and (3) spectrum of toroidal mode numbers of the AEs broadens significantly after the pellet injection. The effects observed are interpreted in terms of a rise in plasma density and an enhancement of the mode amplitude resulting from the resonance sweeping during the pellet injection.

AB - Alfvén eigenmodes (AEs) are routinely seen in present-day tokamaks and stellarators with energetic particles and they represent an attractive form of MHD spectroscopy that provides valuable information on background plasma and on the energetic particles. Possible use of AEs is assessed for MHD spectroscopy of plasma with high-velocity pellet injection employed for fuelling the plasma core. Diagnostics of temporal evolution of the ablated pellets, as well as physics effects determining the diffusion/relaxation of the post pellet profile are of high importance for validating the pellet models and extrapolating them towards ITER. In this paper, JET discharges with ICRH-driven AEs and pellets launched from outboard and inboard tracks are considered. During the pellet injection, an increase in plasma density on a time scale ≪ 50 ms occurs, and several effects on AEs are observed: (1) frequency of the AEs throughout the pellet injection sweeps down by as much as ∼30%, (2) the AE amplitudes increase during the AE frequency sweeping, and (3) spectrum of toroidal mode numbers of the AEs broadens significantly after the pellet injection. The effects observed are interpreted in terms of a rise in plasma density and an enhancement of the mode amplitude resulting from the resonance sweeping during the pellet injection.

KW - Alfven

KW - frequency sweeping

KW - fusion

KW - MHD

KW - subcritical

KW - tokamak

UR - https://www.scopus.com/pages/publications/85050356733

U2 - 10.1088/1741-4326/aabb67

DO - 10.1088/1741-4326/aabb67

M3 - Article

AN - SCOPUS:85050356733

SN - 0029-5515

VL - 58

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 8

M1 - 082008

ER -

MHD spectroscopy of JET plasmas with pellets via Alfvén eigenmodes

Abstract

Funding

UN SDGs

Keywords

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