Results from the Alfven Eigenmode Active Diagnostic during the 2019-2020 JET deuterium campaign
Name
20ja015_full.pdf
Size
677.99 KB
Format
Adobe PDF
Checksum (MD5)
db770000b5c92f6dd37b1977a86f32e3
Author(s)
Tinguely, R. Alex
Puglia, P.G.
Fil, N.
Dowson, S.
Porkolab, Miklos
Fasoli, A.
Testa, D.
JET Contributors
Date Issued
July 2020
Journal
Plasma Physics and Controlled Fusion
Publisher
IOP
Abstract
This paper presents results of extensive analysis of mode excitation observed during the operation of the Alfven Eigenmode Active Diagnostic (AEAD) in the JET tokamak during the 2019-2020 deuterium campaign. Six of eight toroidally spaced antennas, each with independent power and phasing, were successful in actively exciting stable MHD modes in 479 plasmas. In total, 4768 magnetic resonances were detected with up to fourteen fast magnetic probes. In this work, we present the calculations of resonant frequencies f0, damping rates \gamma < 0, and toroidal mode numbers n, spanning the parameter range f0 = 30 - 250 kHz, -\gamma = 0 - 13 kHz, and |n| < 30. In general, good agreement is seen between the resonant and the calculated toroidal Alfven Eigenmode frequencies, and between the toroidal mode numbers applied by the AEAD and estimated of the excited resonances. We note several trends in the database: the probability of resonance detection decreases with plasma current and external heating power; the normalized damping rate increases with edge safety factor but decreases with external heating. These results provide key information to prepare future experimental campaigns and to better understand the physics of excitation and damping of Alfven Eigenmodes in the presence of alpha particles during the upcoming DT campaign, thereby extrapolating with confidence to future tokamaks.
Description
Submitted for publication in Plasma Physics and Controlled Fusion
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/1361-6587/aba7f7
