Very high- and high-confinement mode limited discharges in DIII-D

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.871811· OSTI ID:278957

Jackson, G L; Taylor, T S; Lasnier, C J; Leonard, A W; Burrell, K H; Greenfield, C M; Hill, D N; Hyatt, A W; Kim, J; Osborne, T H; Strait, E J; Whyte, D; Wood, R D ^[1]

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

The first observations of marginally limited very high confinement mode (VH-mode) discharges have been achieved in DIII-D [Nucl. Fusion Special Supplement: {ital World} {ital Survey} {ital of} {ital Activities} {ital in} {ital Controlled} {ital Fusion} {ital Research} (International Atomic Energy Agency, Vienna, 1990)] with significant reductions in peak heat flux conducted to plasma facing surfaces. In addition, quasistationary well limited high confinement-mode (H-mode) discharges have been obtained in DIII-D, also with reduced peak heat flux. This demonstration of reduced peak heat flux while maintaining high performance, i.e., high energy confinement time, can be important for the design of fusion ignition devices. Energy confinement enhancements in these high triangularity discharges are comparable to diverted discharges with similar parameters: {tau}{sub {ital E}}/{tau}{sub ITER-89P}=2.9 for VH-mode and {tau}{sub {ital E}}/{tau}{sub ITER-89P}=1.8 for quasistationary high confinement mode (H mode), where {tau}{sub ITER-89P} is the empirically derived low confinement mode (L-mode) energy confinement scaling relation [Nucl. Fusion {bold 30}, 1999 (1990)]. Comparisons of the conducted heat flux, particle flux, and radiated power profiles show a shift toward the inner wall as the discharge configuration becomes more limited. In addition to the advantage of reduced peak heat flux in these limiter discharges, such configurations also allow more effective use of the internal vessel volume, providing the potential for higher performance, i.e., higher plasma current at a fixed safety factor, {ital q}{sub 95}. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: General Atomics
• DOE Contract Number: AC03-89ER51114; W-7405-ENG-48
• OSTI ID: 278957
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 3 Vol. 3; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DOUBLET-3 DEVICE
HEAT FLUX
LIMITERS
PLASMA CONFINEMENT
PLASMA HEATING
SCALING LAWS
THERMONUCLEAR DEVICES
WALL EFFECTS