Ion heating during magnetic relaxation in the helicity injected torus-II experiment
- University of Washington, AERB Room 120, Box 352250, Seattle, Washington 98195-2250 (United States)
Ion doppler spectroscopy (IDS) is applied to the helicity injected torus (HIT-II) spherical torus to measure impurity ion temperature and flows. [A. J. Redd et al., Phys. Plasmas 9, 2006 (2002)] The IDS instrument employs a 16-channel photomultiplier and can track temperature and velocity continuously through a discharge. Data for the coaxial helicity injection (CHI), transformer, and combined current drive configurations are presented. Ion temperatures for transformer-driven discharges are typically equal to or somewhat lower than electron temperatures measured by Thomson scattering. Internal reconnection events in transformer-driven discharges cause rapid ion heating. The CHI discharges exhibit anomalously high ion temperatures >250 eV, which are an order of magnitude higher than Thomson measurements, indicating ion heating through magnetic relaxation. The CHI discharges that exhibit current and poloidal flux buildup after bubble burst show sustained ion heating during current drive.
- OSTI ID:
- 20782391
- Journal Information:
- Physics of Plasmas, Vol. 12, Issue 12; Other Information: DOI: 10.1063/1.2141932; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHARGED-PARTICLE TRANSPORT
ELECTRIC DISCHARGES
ELECTRON TEMPERATURE
HELICITY
ION TEMPERATURE
IONS
MAGNETOHYDRODYNAMICS
PLASMA
PLASMA CONFINEMENT
PLASMA DIAGNOSTICS
PLASMA HEATING
PLASMA IMPURITIES
RELAXATION
SPECTROSCOPY
SPHEROMAK DEVICES
THOMSON SCATTERING
TRANSFORMERS