Density profile consistency, particle pinch, and cold pulse propagation in DIII-D

Journal Article · Sun Jun 01 04:00:00 EDT 1997 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.872386· OSTI ID:503655

Baker, D R ^[1]

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1. General Atomics, P.O. Box 85608, San Diego, California 92186-9784 (United States)

It has been recently proposed that, for highly turbulent discharges, there exists a consistent density profile for the trapped electrons in a high aspect ratio circular cross-section tokamak, which has a radial variation proportional to 1/q(r), where q is the usual safety factor. It is shown here that this result can be extended to include passing electrons and noncircular cross-section moderate aspect ratio tokamaks. This new prediction for the density profile is compared to the time evolution of the measured electron density profile in low confinement mode (L-mode) shots in the tokamak known as DIII-D [L. Luxon {ital et al.}, {ital Plasma Physics and Controlled Nuclear Fusion Research, 1986} (International Atomic Energy Agency, Vienna, 1987), Vol. I. p. 159], where the q profile is changed in time during the discharge. Once an expression for the consistent density profile is known, it is trivial to obtain an expression for V{sub p}/D, where V{sub p} is the particle pinch velocity and D is the particle diffusion coefficient. This expression is compared with the value of V{sub p}/D, which is obtained from an analysis, utilizing the ONETWO transport code [R. Dominguez and R. Waltz, Nucl. Fusion {bold 27}, 65 (1987)], of certain high confinement mode (H-mode) DIII-D discharges, which are free from edge localized modes. The dependence of density on q can be extended to a dependence of temperature on q through the adiabatic relation. The dependence of temperature on q can then predict one type of cold pulse propagation phenomena. By way of introduction, a simple analogy with a dynamic incompressible fluid system is made.

• Research Organization: General Atomics
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 503655
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 6 Vol. 4; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CROSS SECTIONS
EDGE LOCALIZED MODES
ELECTRIC DISCHARGES
PINCH EFFECT
PLASMA DENSITY
PLASMA DIAGNOSTICS
TOKAMAK DEVICES