Bump-on-tail distributions caused by Alfvénic redistribution of energetic ions

F. Nabais; A. Boboc; R. Calado; J. Eriksson; J. Ferreira; A. Figueiredo; N. Hawkes; C. Hellesen; V. Kiptily; M. Mantsinen; P. Rodrigues; M. Salewski; S.E. Sharapov

doi:10.1088/1741-4326/ac85cb

Bump-on-tail distributions caused by Alfvénic redistribution of energetic ions

F. Nabais^*, A. Boboc, R. Calado, J. Eriksson, J. Ferreira, A. Figueiredo, N. Hawkes, C. Hellesen, V. Kiptily, M. Mantsinen, P. Rodrigues, M. Salewski, S.E. Sharapov

^*Corresponding author for this work

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Abstract

A series of experiments was performed in the JET tokamak aiming to study the characteristics and eventual effects of beam injected ion populations further accelerated through 2nd harmonic ion cyclotron heating. It was found that the injection of these ions could affect sawtooth stability and that these populations excite toroidicity induced Alfvén eigenmodes (TAEs) in the core of the plasma. More interestingly, measurements of DD beam-plasma neutrons from the TOFOR spectrometer show that these modes caused local bump-on-tail distributions in energy. Numerical simulations performed with the CASTOR-K code found a strong interaction between the core-localized TAEs and ions with energies at which local minima in the energy distribution were measured.

Original language	English
Journal	Nuclear Fusion
Volume	62
Issue number	10
Number of pages	8
ISSN	0029-5515
DOIs	https://doi.org/10.1088/1741-4326/ac85cb
Publication status	Published - 2022

Keywords

Tokamaks
Energetic ions
Energetic ion redistribution
Alfvén eigenmodes

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10.1088/1741-4326/ac85cb

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title = "Bump-on-tail distributions caused by Alfv{\'e}nic redistribution of energetic ions",

abstract = "A series of experiments was performed in the JET tokamak aiming to study the characteristics and eventual effects of beam injected ion populations further accelerated through 2nd harmonic ion cyclotron heating. It was found that the injection of these ions could affect sawtooth stability and that these populations excite toroidicity induced Alfv{\'e}n eigenmodes (TAEs) in the core of the plasma. More interestingly, measurements of DD beam-plasma neutrons from the TOFOR spectrometer show that these modes caused local bump-on-tail distributions in energy. Numerical simulations performed with the CASTOR-K code found a strong interaction between the core-localized TAEs and ions with energies at which local minima in the energy distribution were measured.",

keywords = "Tokamaks, Energetic ions, Energetic ion redistribution, Alfv{\'e}n eigenmodes",

author = "F. Nabais and A. Boboc and R. Calado and J. Eriksson and J. Ferreira and A. Figueiredo and N. Hawkes and C. Hellesen and V. Kiptily and M. Mantsinen and P. Rodrigues and M. Salewski and S.E. Sharapov",

year = "2022",

doi = "10.1088/1741-4326/ac85cb",

language = "English",

volume = "62",

journal = "Nuclear Fusion",

issn = "0029-5515",

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TY - JOUR

T1 - Bump-on-tail distributions caused by Alfvénic redistribution of energetic ions

AU - Nabais, F.

AU - Boboc, A.

AU - Calado, R.

AU - Eriksson, J.

AU - Ferreira, J.

AU - Figueiredo, A.

AU - Hawkes, N.

AU - Hellesen, C.

AU - Kiptily, V.

AU - Mantsinen, M.

AU - Rodrigues, P.

AU - Salewski, M.

AU - Sharapov, S.E.

PY - 2022

Y1 - 2022

N2 - A series of experiments was performed in the JET tokamak aiming to study the characteristics and eventual effects of beam injected ion populations further accelerated through 2nd harmonic ion cyclotron heating. It was found that the injection of these ions could affect sawtooth stability and that these populations excite toroidicity induced Alfvén eigenmodes (TAEs) in the core of the plasma. More interestingly, measurements of DD beam-plasma neutrons from the TOFOR spectrometer show that these modes caused local bump-on-tail distributions in energy. Numerical simulations performed with the CASTOR-K code found a strong interaction between the core-localized TAEs and ions with energies at which local minima in the energy distribution were measured.

AB - A series of experiments was performed in the JET tokamak aiming to study the characteristics and eventual effects of beam injected ion populations further accelerated through 2nd harmonic ion cyclotron heating. It was found that the injection of these ions could affect sawtooth stability and that these populations excite toroidicity induced Alfvén eigenmodes (TAEs) in the core of the plasma. More interestingly, measurements of DD beam-plasma neutrons from the TOFOR spectrometer show that these modes caused local bump-on-tail distributions in energy. Numerical simulations performed with the CASTOR-K code found a strong interaction between the core-localized TAEs and ions with energies at which local minima in the energy distribution were measured.

KW - Tokamaks

KW - Energetic ions

KW - Energetic ion redistribution

KW - Alfvén eigenmodes

U2 - 10.1088/1741-4326/ac85cb

DO - 10.1088/1741-4326/ac85cb

M3 - Journal article

SN - 0029-5515

VL - 62

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 10

ER -

Bump-on-tail distributions caused by Alfvénic redistribution of energetic ions

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Keywords

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