
The Library
Density dependence of ion cyclotron emission from deuterium plasmas in the large helical device
Tools
Reman, B. C. G., Dendy, R. O., Akiyama, T. , Chapman, Sandra C., Cook, James William S., Igami, H., Inagaki, S., Saito, K., Seki, R., Kim, M.H., Thatipamula, S.G. and Yun, G.S. (2021) Density dependence of ion cyclotron emission from deuterium plasmas in the large helical device. Nuclear Fusion, 61 (6). 066023. doi:10.1088/1741-4326/abf661 ISSN 0029-5515.
|
PDF
WRAP-density-dependence-ion-cyclotron-emission-deuterium-plasmas-large-helical-device-Dendy-2021.pdf - Accepted Version - Requires a PDF viewer. Download (2106Kb) | Preview |
Official URL: http://dx.doi.org/10.1088/1741-4326/abf661
Abstract
Ion cyclotron emission (ICE) driven by perpendicular neutral beam-injected (NBI) deuterons, together with the distinctive ICE driven by tangential NBI, have been observed from heliotron–stellarator plasmas in the large helical device (LHD). Radio frequency radiation in the lower hybrid range has also been observed Saito K. et al (2018 Plasma Fusion Res. 13 3402043), with frequency dependent on plasma density. Here we focus on recent measurements of ICE from deuterium plasmas in LHD, which show substantial variation in spectral character, between otherwise similar plasmas that have different local density in the emitting region. We analyse this variation by means of first principles simulations, carried out using a particle-in-cell (PIC) kinetic approach. We show, first, that this ICE is driven by perpendicular NBI deuterons, freshly ionised near their injection point in the outer midplane edge of LHD. We find that these NBI deuterons undergo collective sub-Alfvénic relaxation, which we follow deep into the nonlinear phase of the magnetoacoustic cyclotron instability (MCI). The frequency and wavenumber dependence of the saturated amplitudes of the excited fields determine our simulated ICE spectra, and these spectra are obtained for different local densities corresponding to the different LHD ICE-emitting plasmas. The variation with density of the spectral character of the simulated ICE corresponds well with that of the observed ICE from LHD. These results from heliotron–stellarator plasmas complement recent studies of density-dependent ICE from tokamak plasmas in KSTAR Thatipamula S.G. et al (2016 Plasma Phys. Control. Fusion 58 065003); Chapman B. et al (2017 Nucl. Fusion 57 124004), where the spectra vary on sub-microsecond timescales after an ELM crash. Taken together, these results confirm the strongly spatially localised character of ICE physics, and reinforce the potential of ICE as a diagnostic of energetic ion populations and of the ambient plasma.
Item Type: | Journal Article | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Subjects: | Q Science > QC Physics Q Science > QD Chemistry |
|||||||||||||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Physics | |||||||||||||||
Library of Congress Subject Headings (LCSH): | Secondary ion emission, Cyclotrons, Plasma (Ionized gases), Ion cyclotron resonance spectrometry, Cyclotron resonance | |||||||||||||||
Journal or Publication Title: | Nuclear Fusion | |||||||||||||||
Publisher: | Institute of Physics Publishing Ltd. | |||||||||||||||
ISSN: | 0029-5515 | |||||||||||||||
Official Date: | 10 May 2021 | |||||||||||||||
Dates: |
|
|||||||||||||||
Volume: | 61 | |||||||||||||||
Number: | 6 | |||||||||||||||
Article Number: | 066023 | |||||||||||||||
DOI: | 10.1088/1741-4326/abf661 | |||||||||||||||
Status: | Peer Reviewed | |||||||||||||||
Publication Status: | Published | |||||||||||||||
Access rights to Published version: | Restricted or Subscription Access | |||||||||||||||
Date of first compliant deposit: | 1 June 2021 | |||||||||||||||
Date of first compliant Open Access: | 10 May 2022 | |||||||||||||||
RIOXX Funder/Project Grant: |
|
|||||||||||||||
Is Part Of: | 1 |
Request changes or add full text files to a record
Repository staff actions (login required)
![]() |
View Item |
Downloads
Downloads per month over past year