ICRF stabilization of sawteeth on TFTR

Technical Report · Wed Jan 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/5793989· OSTI ID:5793989

Phillips, C K; Hosea, J; Stevens, J; Wilson, J R; Bell, M; Bitter, M; Cheng, C Z; Darrow, D; Fredrickson, E; Hammett, G W; Hill, K; Hsuan, H; Jassby, D; McCune, D; McGuire, K; Owens, D K; Park, H; Ramsey, A; Schilling, G; Schivell, J ; Stratton, B; Synakowski, E; Taylor, G; Towner, H; White, R; Zweben, S ^[1]; Marmar, E; Snipes, J; Terry, J; Bo,

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1. Princeton Univ., NJ (United States). Plasma Physics Lab.

Results obtained from experiments utilizing high power ICRF (ion cyclotron range of frequency) heating to stabilize sawtooth oscillations on TFTR are reviewed. The key observations include existence of a minimum ICRF power required to achieve stabilization, a dependence of the stabilization threshold on the relative size of the ICRF power deposition profile to the q=1 volume, and a peaking of the equilibrium pressure and current profiles during sawtooth-free phases of the discharges. In addition, preliminary measurements of the poloidal magnetic field profile indicate that q on axis decreases to a value of 0.55{plus minus}0.15 after a sawtooth-stabilized period of {approximately}0.5 sec has transpired. The results are discussed in the context of theory, which suggests that the fast ions produced by the ICRF heating suppress sawteeth by stabilizing the m=1 MHD instabilities believed to be the trigger for the sawtooth oscillations. Though qualitative agreement is found between the observations and the theory, further refinement of the theory coupled with more accurate measurements of experimental profiles will be required in order to complete quantitative comparisons.

• Research Organization: Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 5793989
• Report Number(s): PPPL-2820; ON: DE92006648
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
700350 -- Plasma Production
Heating
Current Drive
& Interactions-- (1992-)
CLOSED PLASMA DEVICES
EQUILIBRIUM
HEATING
HIGH-FREQUENCY HEATING
ICR HEATING
INSTABILITY
MAGNETIC FIELDS
MHD EQUILIBRIUM
OSCILLATIONS
PLASMA HEATING
PLASMA INSTABILITY
SAWTOOTH OSCILLATIONS
TFTR TOKAMAK
THERMONUCLEAR DEVICES
TOKAMAK DEVICES