Core turbulence and transport studies on the Texas Experimental Tokamak

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860019· OSTI ID:7034254

Bravenec, R V; Gentle, K W; Richards, B; Ross, D W; Sing, D C; Wootton, A J ^[1]; Brower, D L; Luhmann, Jr, N C; Peebles, W A; Yu, C X ^[2]; Crowley, T P; Heard, J W; Hickok, R L; Schoch, P M ^[3]; Yang, X Z ^[4]

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1. Fusion Research Center, The University of Texas, Austin, Texas 78712 (United States)
2. University of California, Los Angeles, California 90024 (United States)
3. Rensselaer Polytechnic Institute, Troy, New York 12181 (United States)
4. Institute of Physics, Chinese Academy of Science, Beijing (China)

Recent experiments on the Texas Experimental Tokamak (TEXT) (Plasma Phys. Controlled Fusion {bold 27}, 1335 (1985)) have focused on identifying the drives and transport significance of the turbulence in the interior of discharges in the neo-Alcator confinement regime. Far-infrared (FIR) scattering consistently observes density fluctuations indicative of electron drift waves, i.e., {omega}{sub {ital k}}{similar to}{omega}{sub {ital e}}{sup *}+{ital k}{sub {theta}}{ital v}{sub {ital E}}, where {ital v}{sub {ital E}}{equivalent to}{minus}{ital E}{sub {ital r}}/{ital B} (the electron diamagnetic frequency Doppler-shifted by the {bold E}{times}{bold B} poloidal plasma rotation) and an amplitude that scales inversely with the density scale length {ital L}{sub {ital n}}. Although consistent with scattering on the power-weighted frequency {bar {omega}}, heavy-ion beam probe (HIBP) data typically indicate {ital {bar k}}{sub {theta}}{rho}{sub {ital s}}{lt}0.1 such that {bar {omega}}{much gt}{bar {omega}}{sub {ital e}}{sup *}+{ital {bar k}}{sub {theta}}{ital v}{sub {ital E}} and {ital {bar n}}/{ital n}{sub {ital e}}{much lt}1/{ital {bar k}}{sub {theta}}{ital L}{sub {ital n}}. Experiments with a modulated gas feed and/or electron-cyclotron resonance heating (ECRH) seem to rule out {del}{ital T}{sub {ital e}} as the turbulent drive, although little evidence for {del}{ital n}{sub {ital e}} is apparent either. In fact, the interior fluctuations seen by the HIBP seem to depend more on edge conditions than local gradients. The quasilinear fluxes due to dissipative trapped electrons are found to be sufficient to account for the equilibrium fluxes in the region of low collisionality ({nu}{sub {ital e}}{sup *}{much lt}1) for a drift-wave spectrum ({ital {bar k}}{sub {theta}}{rho}{sub {ital s}}{similar to}0.3), but not for the low wave numbers seen by the HIBP.

• DOE Contract Number: FG05-88ER53267
• OSTI ID: 7034254
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 4:7; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700310 -- Plasma Confinement-- (1992-)
700330 -- Plasma Kinetics
Transport
& Impurities-- (1992-)
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
CLOSED PLASMA DEVICES
CONFINEMENT
ELECTROMAGNETIC RADIATION
FAR INFRARED RADIATION
FLUCTUATIONS
HEATING
INFRARED RADIATION
PLASMA CONFINEMENT
PLASMA HEATING
RADIATIONS
TEXT DEVICES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TURBULENCE
VARIATIONS