Argon Pumpout by ICRF Waves in C-Mod L- and I-mode Plasmas
Name
22ja011_full.pdf
Size
4.19 MB
Format
Adobe PDF
Checksum (MD5)
d437c17b23a5fd2f73c5f9b7ed129603
Author(s)
Rice, John E.
Lin, Y.
Perks, C.J.
Reinke, M.L.
Marmar, E.S.
Cao, N.
Gao, C.
Sciortino, Francesco
Wukitch, S.J.
Wright, John C.
Date Issued
February 2022
Journal
Nuclear Fusion
Publisher
IOP
Abstract
Pumpout of argon ions by ICRF waves has been observed in C-Mod deuterium L- and I-mode plasmas that had a substantial hydrogen fraction. The effect is manifested by a reduction of core argon x-ray brightness up to a factor of 90% on time scales of tens of milliseconds following injection of ICRF power. For Ar^16+, the pumpout is strongest for hydrogen minority concentrations between 0.25 and 0.4, when the ICRF waves are not expected to result in minority heating. Modeling with the TORIC code suggests that the pumpout process occurs when the H/D mode conversion layer overlaps with the 2nd harmonic impurity resonance layer. The magnitude of the argon pumpout is independent of ICRF power above an apparent threshold of ~500 kW, independent of electron density and appears to decrease as the plasma current is increased. Potential application as a heavy impurity control tool in reactors is discussed.
Description
Submitted for publication in Nuclear Fusion
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/1741-4326/ac6ef0
