Abstract
The excitation and stabilization of Alfven eigenmodes and their impact on energetic ion confinement were investigated with negative ion based neutral beam injection at 330-360 keV into weak or reversed magnetic shear plasmas on JT-60U. Toroidicity induced Alfven eigenmodes (TAEs) were observed in weak shear plasmas with 〈βh〉≥0.1% and 0.4≤vb∥/vA≤1. The stability of TAEs is consistent with predictions by the NOVA-K code. New burst modes and chirping modes were observed in the higher β regime of 〈βh〉≥0.2%. The effect of TAEs, burst modes and chirping modes on fast ion confinement has been found to be small so far. It was found that a strongly reversed shear plasma with internal transport barrier suppresses AEs.
Original language | English |
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Pages (from-to) | 1837-1843 |
Number of pages | 7 |
Journal | Nuclear Fusion |
Volume | 39 |
Issue number | Special Issu |
DOIs | |
Publication status | Published - 1999 |