Argon Pumpout by ICRF Waves in C-Mod L- and I-mode Plasmas

Dataset · Wed Jun 08 00:00:00 EDT 2022

DOI:https://doi.org/10.7910/DVN/B4II5P· OSTI ID:1887970

Rice, J. E. ^[1]; Lin, Y.; Perks, C. J.; Reinke, M. L.; Marmar, E. S.; Cao, N.; Gao, C.; Sciortino, F.; Wukitch, S. J.; Wright, J.

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1. OSTI

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.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• DOE Contract Number: SC0014264
• OSTI ID: 1887970
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY