Abstract
A high ion temperature (Ti) mode is observed for neutral beam heated plasmas in the Compact Helical System (CHS) heliotron/torsatron. The high Ti mode plasma is characterized by a high central ion temperature, Ti(O), and is associated with a peaked electron density profile produced by neutral beam fuelling with low wall recycling. Transition from L mode to high Ti mode has been studied in CHS. Ti(0) in the high Ti mode discharges reaches 1 keV, which is 2.5 times higher than that in the L mode discharges. The ion thermal diffusivity is significantly reduced by a factor of more than 2-3 in the high Ti mode plasma. The ion loss cone is observed in neutral particle flux in the energy range 1-6 keV with a narrow range of pitch angle (90°±20°) in the high Ti mode. However, the degradation of ion energy confinement due to this loss cone is negligible.
Original language | English |
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Pages (from-to) | 1649-1658 |
Number of pages | 10 |
Journal | Nuclear Fusion |
Volume | 39 |
Issue number | Special Issu |
DOIs | |
Publication status | Published - 1999 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Condensed Matter Physics