Thermal diffusivities in DIII-D show evidence of critical gradients

被引:39
作者
Baker, DR
Greenfield, CM
Burrell, KH
DeBoo, JC
Doyle, EJ
Groebner, RJ
Luce, TC
Petty, CC
Stallard, BW
Thomas, DM
Wade, MR
机构
[1] Gen Atom Co, San Diego, CA 92186 USA
[2] Univ Calif Los Angeles, Los Angeles, CA 90024 USA
[3] Lawrence Livermore Natl Lab, Livermore, CA USA
[4] Oak Ridge Associated Univ, Oak Ridge, TN 37831 USA
关键词
D O I
10.1063/1.1395567
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
The ion thermal diffusivities (chi (i)) in DIII-D [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)] discharges exhibit a strong nonlinear dependence on the measured temperature gradients. In low confinement mode (L-mode) discharges with low toroidal rotation, the ion thermal diffusivity, chi (i), has an approximately Heaviside function dependence on the major radius divided by the radial scale length of the ion temperature, R/L-Ti. When R/L-Ti is less than a critical value, the chi (i)'s are very small. When R/L-Ti is about equal to the critical value, chi (i) increases rapidly. Although the gradient profiles for high confinement (H-mode) have a different shape, they still show a critical gradient type of behavior. This type of dependence is consistent with the predictions for transport, which is dominated by ion temperature gradient modes and is a strong indicator that these modes are the main contributors toward L-mode transport in DIII-D and a major contributor to transport in a certain region of DIII-D H-mode discharges. When strong rotational shear is present, the thermal confinement is improved in regions of the plasma. In these regions, the dependence of the diffusivities on the gradients is changed. The type of change is consistent with the physical picture that when the ExB shearing frequency is greater than the maximum linear growth rate of the modes as calculated without shear, then the modes are stabilized and the transport is reduced. (C) 2001 American Institute of Physics.
引用
收藏
页码:4128 / 4137
页数:10
相关论文
共 17 条
  • [1] Progress in anomalous transport research in toroidal magnetic confinement devices
    Carreras, BA
    [J]. IEEE TRANSACTIONS ON PLASMA SCIENCE, 1997, 25 (06) : 1281 - 1321
  • [2] Scalings of ion-temperature-gradient-driven anomalous transport in tokamaks
    Dimits, AM
    Williams, TJ
    Byers, JA
    Cohen, BI
    [J]. PHYSICAL REVIEW LETTERS, 1996, 77 (01) : 71 - 74
  • [3] Comparisons and physics basis of tokamak transport models and turbulence simulations
    Dimits, AM
    Bateman, G
    Beer, MA
    Cohen, BI
    Dorland, W
    Hammett, GW
    Kim, C
    Kinsey, JE
    Kotschenreuther, M
    Kritz, AH
    Lao, LL
    Mandrekas, J
    Nevins, WM
    Parker, SE
    Redd, AJ
    Shumaker, DE
    Sydora, R
    Weiland, J
    [J]. PHYSICS OF PLASMAS, 2000, 7 (03) : 969 - 983
  • [4] GOHIL P, 1992, FUSION ENG, V2, P1199
  • [5] Understanding and control of transport in Advanced Tokamak regimes in DIII-D
    Greenfield, CM
    DeBoo, JC
    Luce, TC
    Stallard, BW
    Synakowski, EJ
    Baylor, LR
    Burrell, KH
    Casper, TA
    Doyle, EJ
    Ernst, DR
    Ferron, JR
    Gohil, P
    Groebner, RJ
    Lao, LL
    Makowski, M
    McKee, GR
    Murakami, M
    Petty, CC
    Pinsker, RI
    Politzer, PA
    Prater, R
    Rettig, CL
    Rhodes, TL
    Rice, BW
    Schmidt, GL
    Staebler, GM
    Strait, EJ
    Thomas, DM
    Wade, MR
    [J]. PHYSICS OF PLASMAS, 2000, 7 (05) : 1959 - 1967
  • [6] EXPERIMENTALLY INFERRED ION THERMAL-DIFFUSIVITY PROFILES IN THE DOUBLET-III TOKAMAK - COMPARISON WITH NEOCLASSICAL THEORY
    GROEBNER, RJ
    PFEIFFER, W
    BLAU, FP
    BURRELL, KH
    FAIRBANKS, ES
    SERAYDARIAN, RP
    STJOHN, H
    STOCKDALE, RE
    [J]. NUCLEAR FUSION, 1986, 26 (05) : 543 - 554
  • [7] FLOW SHEAR-INDUCED FLUCTUATION SUPPRESSION IN FINITE ASPECT RATIO SHAPED TOKAMAK PLASMA
    HAHM, TS
    BURRELL, KH
    [J]. PHYSICS OF PLASMAS, 1995, 2 (05) : 1648 - 1651
  • [8] Hawryluk R. J., 1980, PHYSICS PLASMAS CLOS, V1, P19
  • [9] THEORY OF PLASMA TRANSPORT IN TOROIDAL CONFINEMENT SYSTEMS
    HINTON, FL
    HAZELTINE, RD
    [J]. REVIEWS OF MODERN PHYSICS, 1976, 48 (02) : 239 - 308
  • [10] JOHN H. E. ST., 1995, PLASMA PHYS CONTROLL, V3, P603