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Title: Experimental studies of plasma-antenna coupling with the JET Alfven Eigenmode Active Diagnostic

Abstract

This paper presents a dedicated study of plasma-antenna (PA) coupling with the Alfven Eigenmode Active Diagnostic (AEAD) in JET. Stable AEs and their resonant frequencies f, damping rates gamma < 0, and toroidal mode numbers n are measured for various PA separations and limiter versus X-point magnetic configurations. Two stable AEs are observed to be resonantly excited at distinct low and high frequencies in limiter plasmas. The values of f and n do not vary with PA separation. However, |gamma| increases with PA separation for the low-f, but not high-f, mode, yet this may be due to slightly different edge conditions. The high-f AE is detected throughout the transition from limiter to X-point configuration, though its damping rate increases; the low-f mode, on the other hand, becomes unidentifiable. The linear resistive MHD code CASTOR is used to simulate the frequency scan of an AEAD-like external antenna. For the limiter pulses, the high-f mode is determined to be an n = 0 GAE, while the low-f mode is likely an n = 2 TAE. During the transition from limiter to X-point configuration, CASTOR indicates that n = 1 and 2 EAEs are excited in the edge gap. These results extend previousmore » experimental studies in JET and Alcator C-Mod; validate the computational work performed by Dvornova et al 2020 Phys. Plasmas 27 012507; and provide guidance for the optimization of PA coupling in upcoming JET energetic particle experiments, for which the AEAD will aim to identify the contribution of alpha particles to AE drive during the DT campaign.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
DOE Contract Number:  
FG02-99ER54563; AC05-00OR22725; AC02-05CH11231
Research Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1887517
DOI:
https://doi.org/10.7910/DVN/JI9GP8

Citation Formats

Tinguely, R. A., Puglia, P. G., Fil, N., Dowson, S., Porkolab, M., Dvornova, A., Fasoli, A., Fitzgerald, M., Guillemot, V., Huysmans, G. T. A., Maslov, M., Sharapov, S., Testa, D., and JET Contributors. Experimental studies of plasma-antenna coupling with the JET Alfven Eigenmode Active Diagnostic. United States: N. p., 2021. Web. doi:10.7910/DVN/JI9GP8.
Tinguely, R. A., Puglia, P. G., Fil, N., Dowson, S., Porkolab, M., Dvornova, A., Fasoli, A., Fitzgerald, M., Guillemot, V., Huysmans, G. T. A., Maslov, M., Sharapov, S., Testa, D., & JET Contributors. Experimental studies of plasma-antenna coupling with the JET Alfven Eigenmode Active Diagnostic. United States. doi:https://doi.org/10.7910/DVN/JI9GP8
Tinguely, R. A., Puglia, P. G., Fil, N., Dowson, S., Porkolab, M., Dvornova, A., Fasoli, A., Fitzgerald, M., Guillemot, V., Huysmans, G. T. A., Maslov, M., Sharapov, S., Testa, D., and JET Contributors. 2021. "Experimental studies of plasma-antenna coupling with the JET Alfven Eigenmode Active Diagnostic". United States. doi:https://doi.org/10.7910/DVN/JI9GP8. https://www.osti.gov/servlets/purl/1887517. Pub date:Fri Jun 25 00:00:00 EDT 2021
@article{osti_1887517,
title = {Experimental studies of plasma-antenna coupling with the JET Alfven Eigenmode Active Diagnostic},
author = {Tinguely, R. A. and Puglia, P. G. and Fil, N. and Dowson, S. and Porkolab, M. and Dvornova, A. and Fasoli, A. and Fitzgerald, M. and Guillemot, V. and Huysmans, G. T. A. and Maslov, M. and Sharapov, S. and Testa, D. and JET Contributors},
abstractNote = {This paper presents a dedicated study of plasma-antenna (PA) coupling with the Alfven Eigenmode Active Diagnostic (AEAD) in JET. Stable AEs and their resonant frequencies f, damping rates gamma < 0, and toroidal mode numbers n are measured for various PA separations and limiter versus X-point magnetic configurations. Two stable AEs are observed to be resonantly excited at distinct low and high frequencies in limiter plasmas. The values of f and n do not vary with PA separation. However, |gamma| increases with PA separation for the low-f, but not high-f, mode, yet this may be due to slightly different edge conditions. The high-f AE is detected throughout the transition from limiter to X-point configuration, though its damping rate increases; the low-f mode, on the other hand, becomes unidentifiable. The linear resistive MHD code CASTOR is used to simulate the frequency scan of an AEAD-like external antenna. For the limiter pulses, the high-f mode is determined to be an n = 0 GAE, while the low-f mode is likely an n = 2 TAE. During the transition from limiter to X-point configuration, CASTOR indicates that n = 1 and 2 EAEs are excited in the edge gap. These results extend previous experimental studies in JET and Alcator C-Mod; validate the computational work performed by Dvornova et al 2020 Phys. Plasmas 27 012507; and provide guidance for the optimization of PA coupling in upcoming JET energetic particle experiments, for which the AEAD will aim to identify the contribution of alpha particles to AE drive during the DT campaign.},
doi = {10.7910/DVN/JI9GP8},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2021},
month = {6}
}

Works referencing / citing this record:

Experimental studies of plasma-antenna coupling with the JET Alfvén Eigenmode Active Diagnostic
journal, December 2020