Mode conversion studies in TFTR
Mode converted Ion Bernstein Waves (IBW) have important potential applications in tokamak reactors. These applications include on or off axis electron heating and current drive and the channeling of alpha particle power for both current drive and increased reactivity. Efficient mode conversion electron heating with a low field side antenna, with both on and off axis power deposition, has been demonstrated for the first time in TFTR in D{sup 3}He-{sup 4}He plasmas. Up to 80% of the Ion Cyclotron Range of Frequency (ICRF) power is coupled to electrons at the mode conversion surface. Experiments during deuterium and tritium neutral beam injection (NBI) indicate that good mode conversion efficiency can be maintained during NBI if sufficient {sup 3}He is present. No evidence of strong alpha particle heating by the IBW is seen. Recent modeling indicates that if the mode converted IBW is preferentially excited off the horizontal midplane then the resultant high poloidal mode number wave may channel alpha particle power to either electrons or ions. In TFTR both the propagation of the IBW and its effect on the alpha particle population is being investigated. Experiments with 2 MW of ICRF power launched with {+-} 90{degree} antenna phasing for current drive show that electron heating and sawtooth activity depend strongly on the direction of the launched wave. The noninductively driven current could not be experimentally determined in these relatively high plasma current, short pulse discharges. Experiments at higher RF power and lower plasma current are planned to determine on and off axis current drive efficiency.
- Research Organization:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH03073
- OSTI ID:
- 34428
- Report Number(s):
- PPPL-3086; IAEA-CN-60/A-3-I-4; CONF-940933-39; ON: DE95009386; TRN: 95:009070
- Resource Relation:
- Conference: 15. international conference on plasma physics and controlled nuclear fusion research, Madrid (Spain), 26 Sep - 1 Oct 1994; Other Information: PBD: Mar 1995
- Country of Publication:
- United States
- Language:
- English
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