Role of core toroidal rotation on the H-mode radial electric field shear, turbulence, and confinement as studied by magnetic braking in the DIII-D tokamak

Journal Article · Tue Feb 01 04:00:00 EST 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870925· OSTI ID:5185364

La Haye, R J; Rettig, C L; Groebner, R J; Hyatt, A W; Scoville, J T ^[1]

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1. General Atomics, San Diego, California 92186-9784 (United States)

Magnetic braking'' of the plasma toroidal rotation in the high confinement H mode by applied resonant, low [ital m],[ital n]=1 static error fields is used in DIII-D [Nucl. Fusion [bold 31], 875 (1991)] as an independent control to evaluate the [bold E][sub [ital r]][times][bold B] stabilization of microturbulence in the plasma core. In the core ([rho][approx lt]0.9) of a tokamak, the radial electric field and its shear are dominated by toroidal rotation. The fundamental quantity for shear stabilization of microturbulence is shear in the velocity of the fluctuations [bold v][sub [perpendicular]][approx][bold E][sub [ital r]][times][bold B]/[bold B][center dot][bold B] which in the core is [ital v][sub [perpendicular]][approx][ital v][sub [phi]][ital B][sub [theta]]/ [ital B][sub [phi]]. With magnetic braking greatly decreasing the toroidal rotation and thus reducing the core radial electric field and shear, far infrared (FIR) measurements of density microturbulence show downshifting in frequency near [rho][approx]0.8 as a result of the reduced Doppler shift ([omega][approx][ital k][sub [theta]][ital E][sub [ital r]]/[ital B][sub [phi]]) and a factor of 2 increase in the turbulence level ([ital [tilde n]]/[ital n])[sup 2] in the period between edge localized modes (ELMs). There is also a large reduction in turbulence at an ELM which tends to compensate for the increase in turbulence with reduced radial electric field shear between ELMs. No significant change is found in H-mode plasma energy, confinement time, internal inductance [ital l][sub [ital i]], density profile, [ital T][sub [ital e]] profile, or [ital T][sub [ital i]] profile. Good H-mode confinement is maintained by the edge ([rho][approx gt]0.95) transport barrier where the reversed edge [ital E][sub [ital r]] and high edge [ital E][sub [ital r]] shear remain unchanged.

• DOE Contract Number: AC03-89ER51114; FC03-86ER52126
• OSTI ID: 5185364
• Journal Information: Physics of Plasmas; (United States), Journal Name: Physics of Plasmas; (United States) Vol. 1:2; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700310 -- Plasma Confinement-- (1992-)
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
CLOSED PLASMA DEVICES
CONFINEMENT
DOPPLER EFFECT
ELECTRIC FIELDS
EXPERIMENTAL REACTORS
FLUCTUATIONS
FLUID FUELED REACTORS
GAS FUELED REACTORS
HOMOGENEOUS REACTORS
PLASMA
PLASMA CONFINEMENT
PLASMA CORE ASSEMBLY
REACTORS
RESEARCH AND TEST REACTORS
ROTATING PLASMA
STABILIZATION
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSPORT
TURBULENCE
VARIATIONS
ZERO POWER REACTORS