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Title: Physics of advanced tokamaks

Abstract

Significant reductions in the size and cost of a fusion power plant core can be realized if simultaneous improvements in the energy replacement time, {tau}{sub E}, and the plasma pressure or beta, {beta}{sub T} = 2 {micro}{sub 0} /B{sup 2} can be achieved in steady-state conditions with high self-driven, bootstrap current fraction. Significant recent progress has been made in experimentally achieving these high performance regimes and in developing a theoretical understanding of the underlying physics. Three operational scenarios have demonstrated potential for steady state high performance, the radiative improved (RI) mode, the high internal inductance or high {ell}{sub i} scenario, and the negative central magnetic shear, NCS (or reversed shear, RS) scenario. In a large number of tokamaks, reduced ion thermal transport to near neoclassical values, and reduced particle transport have been observed in the region of negative or very low magnetic shear: the transport reduction is consistent with stabilization of microturbulence by sheared E x B flow. There is strong temporal and spatial correlation between the increased sheared E x B flow, the reduction in the measured turbulence, and the reduction in transport. The DIII-D tokamak, the JET tokamak and the JT-60U tokamak have all observed significant increases inmore » plasma performance in the NCS operational regime. Strong plasma shaping and broad pressure profiles, provided by the H-mode edge, allow high beta operation, consistent with theoretical predictions; and normalized beta values up to {beta}{sub T}/(I/aB) {equivalent_to} {beta}{sub N} {approximately} 4.5%-m-T/MA simultaneously with confinement enhancement over L-mode scaling, H = {tau}/{tau}{sub ITER-89P} {approximately} 4, have been achieved in the DIII-D tokamak. In the JT-60U tokamak, deuterium discharges with negative central magnetic shear, NCS, have reached equivalent break-even conditions, Q{sub DT} (equiv) = 1.« less

Authors:
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States); Los Alamos National Lab., NM (United States); Oak Ridge National Lab., TN (United States); Princeton Univ., Princeton Plasma Physics Lab., NJ (United States); Columbia Univ., NY (United States); Massachusetts Inst. of Tech., Cambridge, MA (United States); Univ. of Texas, Austin, TX (United States)
Sponsoring Org.:
USDOE Office of Energy Research, Washington, DC (United States)
OSTI Identifier:
674703
Report Number(s):
GA-A22704; CONF-9706131-
ON: DE98003429; TRN: 99:001031
DOE Contract Number:  
AC03-89ER51114; W-7405-ENG-48; AC05-96OR22464; AC02-76CH03073; FG02-89ER53297; FG02-91ER54109; FG05-88ER53266
Resource Type:
Conference
Resource Relation:
Conference: 24. EPS conference on controlled fusion and plasma physics, Berchtesgaden (Germany), 9-13 Jun 1997; Other Information: PBD: Nov 1997
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; DOUBLET-3 DEVICE; JET TOKAMAK; JT-60U TOKAMAK; PERFORMANCE; OPERATION; STEADY-STATE CONDITIONS; SHEAR; PLASMA DRIFT; PLASMA PRESSURE; CONFINEMENT TIME

Citation Formats

Taylor, T S. Physics of advanced tokamaks. United States: N. p., 1997. Web.
Taylor, T S. Physics of advanced tokamaks. United States.
Taylor, T S. Sat . "Physics of advanced tokamaks". United States. https://www.osti.gov/servlets/purl/674703.
@article{osti_674703,
title = {Physics of advanced tokamaks},
author = {Taylor, T S},
abstractNote = {Significant reductions in the size and cost of a fusion power plant core can be realized if simultaneous improvements in the energy replacement time, {tau}{sub E}, and the plasma pressure or beta, {beta}{sub T} = 2 {micro}{sub 0} /B{sup 2} can be achieved in steady-state conditions with high self-driven, bootstrap current fraction. Significant recent progress has been made in experimentally achieving these high performance regimes and in developing a theoretical understanding of the underlying physics. Three operational scenarios have demonstrated potential for steady state high performance, the radiative improved (RI) mode, the high internal inductance or high {ell}{sub i} scenario, and the negative central magnetic shear, NCS (or reversed shear, RS) scenario. In a large number of tokamaks, reduced ion thermal transport to near neoclassical values, and reduced particle transport have been observed in the region of negative or very low magnetic shear: the transport reduction is consistent with stabilization of microturbulence by sheared E x B flow. There is strong temporal and spatial correlation between the increased sheared E x B flow, the reduction in the measured turbulence, and the reduction in transport. The DIII-D tokamak, the JET tokamak and the JT-60U tokamak have all observed significant increases in plasma performance in the NCS operational regime. Strong plasma shaping and broad pressure profiles, provided by the H-mode edge, allow high beta operation, consistent with theoretical predictions; and normalized beta values up to {beta}{sub T}/(I/aB) {equivalent_to} {beta}{sub N} {approximately} 4.5%-m-T/MA simultaneously with confinement enhancement over L-mode scaling, H = {tau}/{tau}{sub ITER-89P} {approximately} 4, have been achieved in the DIII-D tokamak. In the JT-60U tokamak, deuterium discharges with negative central magnetic shear, NCS, have reached equivalent break-even conditions, Q{sub DT} (equiv) = 1.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1997},
month = {11}
}

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