Observations and modelling of ion cyclotron emission observed in JET plasmas using a sub-harmonic arc detection system during ion cyclotron resonance heating

JET contributors

doi:10.1088/1741-4326/aace03

Observations and modelling of ion cyclotron emission observed in JET plasmas using a sub-harmonic arc detection system during ion cyclotron resonance heating

JET contributors

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

16 Scopus citations

Abstract

Measurements are reported of electromagnetic emission close to the cyclotron frequency of energetic ions in JET plasmas heated by waves in the ion cylotron range of frequencies (ICRF). Hydrogen was the majority ion species in all of these plasmas. The measurements were obtained using a sub-harmonic arc detection system in the transmission lines of one of the ICRF antennas. The measured ion cyclotron emission spectra were strongly filtered by the antenna system, and typically contained sub-structure, consisting of sets of peaks with a separation of a few kHz, suggesting the excitation of compressional Alfvén eigenmodes closely spaced in frequency. In most cases the energetic ions can be clearly identified as ICRF wave-accelerated ³He minority ions, although in two pulses the emission may have been produced by energetic ⁴He ions, originating from third harmonic ICRF wave acceleration. It is proposed that the emission close to the ³He cyclotron frequency was produced by energetic ions of this species undergoing drift orbit excursions to the outer midplane plasma edge. Particle-in-cell and hybrid (kinetic ion, fluid electron) simulations using plasma parameters corresponding to edge plasma conditions in these JET pulses, and energetic particle parameters inferred from the cyclotron resonance location, indicate strong excitation of waves at multiple ³He cyclotron harmonics, including the fundamental, which is identified with the observed emission. These results underline the potential importance of ICE measurements as a method of studying confined fast particles that are strongly suprathermal but have insufficient energies or are not present in sufficient numbers to excite detectable levels of γ-ray emission or other collective instabilities.

Original language	English
Article number	096020
Journal	Nuclear Fusion
Volume	58
Issue number	9
DOIs	https://doi.org/10.1088/1741-4326/aace03
State	Published - 10 Jul 2018
Externally published	Yes

Keywords

energetic particles
ion cyclotron emission
ion cyclotron resonance heating
particle-in-cell simulations

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10.1088/1741-4326/aace03

Cite this

@article{f5c0c1591c224dca87bcd6fdaebb85b4,

title = "Observations and modelling of ion cyclotron emission observed in JET plasmas using a sub-harmonic arc detection system during ion cyclotron resonance heating",

abstract = "Measurements are reported of electromagnetic emission close to the cyclotron frequency of energetic ions in JET plasmas heated by waves in the ion cylotron range of frequencies (ICRF). Hydrogen was the majority ion species in all of these plasmas. The measurements were obtained using a sub-harmonic arc detection system in the transmission lines of one of the ICRF antennas. The measured ion cyclotron emission spectra were strongly filtered by the antenna system, and typically contained sub-structure, consisting of sets of peaks with a separation of a few kHz, suggesting the excitation of compressional Alfv{\'e}n eigenmodes closely spaced in frequency. In most cases the energetic ions can be clearly identified as ICRF wave-accelerated 3He minority ions, although in two pulses the emission may have been produced by energetic 4He ions, originating from third harmonic ICRF wave acceleration. It is proposed that the emission close to the 3He cyclotron frequency was produced by energetic ions of this species undergoing drift orbit excursions to the outer midplane plasma edge. Particle-in-cell and hybrid (kinetic ion, fluid electron) simulations using plasma parameters corresponding to edge plasma conditions in these JET pulses, and energetic particle parameters inferred from the cyclotron resonance location, indicate strong excitation of waves at multiple 3He cyclotron harmonics, including the fundamental, which is identified with the observed emission. These results underline the potential importance of ICE measurements as a method of studying confined fast particles that are strongly suprathermal but have insufficient energies or are not present in sufficient numbers to excite detectable levels of γ-ray emission or other collective instabilities.",

keywords = "energetic particles, ion cyclotron emission, ion cyclotron resonance heating, particle-in-cell simulations",

author = "{JET contributors} and McClements, {K. G.} and A. Brisset and B. Chapman and Chapman, {S. C.} and Dendy, {R. O.} and P. Jacquet and Kiptily, {V. G.} and M. Mantsinen and Reman, {B. C.G.} 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 L. Aho-Mantila and N. Aiba and M. 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 C. Appelbee and P. Arena and M. Ariola and H. Arnichand and S. Arshad and A. Ash and N. Ashikawa and V. Aslanyan and O. Asunta and F. Auriemma and Wiechec, {A. Baron}",

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

year = "2018",

month = jul,

day = "10",

doi = "10.1088/1741-4326/aace03",

language = "英语",

volume = "58",

journal = "Nuclear Fusion",

issn = "0029-5515",

publisher = "IOP Publishing Ltd.",

number = "9",

}

TY - JOUR

T1 - Observations and modelling of ion cyclotron emission observed in JET plasmas using a sub-harmonic arc detection system during ion cyclotron resonance heating

AU - JET contributors

AU - McClements, K. G.

AU - Brisset, A.

AU - Chapman, B.

AU - Chapman, S. C.

AU - Dendy, R. O.

AU - Jacquet, P.

AU - Kiptily, V. G.

AU - Mantsinen, M.

AU - Reman, B. C.G.

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, L.

AU - Aiba, N.

AU - Airila, M.

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 - Appelbee, C.

AU - Arena, P.

AU - Ariola, M.

AU - Arnichand, H.

AU - Arshad, S.

AU - Ash, A.

AU - Ashikawa, N.

AU - Aslanyan, V.

AU - Asunta, O.

AU - Auriemma, F.

AU - Wiechec, A. Baron

PY - 2018/7/10

Y1 - 2018/7/10

N2 - Measurements are reported of electromagnetic emission close to the cyclotron frequency of energetic ions in JET plasmas heated by waves in the ion cylotron range of frequencies (ICRF). Hydrogen was the majority ion species in all of these plasmas. The measurements were obtained using a sub-harmonic arc detection system in the transmission lines of one of the ICRF antennas. The measured ion cyclotron emission spectra were strongly filtered by the antenna system, and typically contained sub-structure, consisting of sets of peaks with a separation of a few kHz, suggesting the excitation of compressional Alfvén eigenmodes closely spaced in frequency. In most cases the energetic ions can be clearly identified as ICRF wave-accelerated 3He minority ions, although in two pulses the emission may have been produced by energetic 4He ions, originating from third harmonic ICRF wave acceleration. It is proposed that the emission close to the 3He cyclotron frequency was produced by energetic ions of this species undergoing drift orbit excursions to the outer midplane plasma edge. Particle-in-cell and hybrid (kinetic ion, fluid electron) simulations using plasma parameters corresponding to edge plasma conditions in these JET pulses, and energetic particle parameters inferred from the cyclotron resonance location, indicate strong excitation of waves at multiple 3He cyclotron harmonics, including the fundamental, which is identified with the observed emission. These results underline the potential importance of ICE measurements as a method of studying confined fast particles that are strongly suprathermal but have insufficient energies or are not present in sufficient numbers to excite detectable levels of γ-ray emission or other collective instabilities.

AB - Measurements are reported of electromagnetic emission close to the cyclotron frequency of energetic ions in JET plasmas heated by waves in the ion cylotron range of frequencies (ICRF). Hydrogen was the majority ion species in all of these plasmas. The measurements were obtained using a sub-harmonic arc detection system in the transmission lines of one of the ICRF antennas. The measured ion cyclotron emission spectra were strongly filtered by the antenna system, and typically contained sub-structure, consisting of sets of peaks with a separation of a few kHz, suggesting the excitation of compressional Alfvén eigenmodes closely spaced in frequency. In most cases the energetic ions can be clearly identified as ICRF wave-accelerated 3He minority ions, although in two pulses the emission may have been produced by energetic 4He ions, originating from third harmonic ICRF wave acceleration. It is proposed that the emission close to the 3He cyclotron frequency was produced by energetic ions of this species undergoing drift orbit excursions to the outer midplane plasma edge. Particle-in-cell and hybrid (kinetic ion, fluid electron) simulations using plasma parameters corresponding to edge plasma conditions in these JET pulses, and energetic particle parameters inferred from the cyclotron resonance location, indicate strong excitation of waves at multiple 3He cyclotron harmonics, including the fundamental, which is identified with the observed emission. These results underline the potential importance of ICE measurements as a method of studying confined fast particles that are strongly suprathermal but have insufficient energies or are not present in sufficient numbers to excite detectable levels of γ-ray emission or other collective instabilities.

KW - energetic particles

KW - ion cyclotron emission

KW - ion cyclotron resonance heating

KW - particle-in-cell simulations

UR - http://www.scopus.com/inward/record.url?scp=85051175701&partnerID=8YFLogxK

U2 - 10.1088/1741-4326/aace03

DO - 10.1088/1741-4326/aace03

M3 - 文章

AN - SCOPUS:85051175701

SN - 0029-5515

VL - 58

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 9

M1 - 096020

ER -

Observations and modelling of ion cyclotron emission observed in JET plasmas using a sub-harmonic arc detection system during ion cyclotron resonance heating

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Keywords

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