Thermal transport in the DIII-D edge pedestal

A new procedure for inferring χi,eexp in the plasma edge from experimental data and integrated modeling code calculations has been developed that takes into account atomic physics and radiation effects and convective as well as conductive heat flux profiles. Application to DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] shots indicates that proper inference of χi,eexp in the edge pedestal (sharp gradient region) depends on accounting for the variation in electron and ion heat fluxes and in the convective fraction of each over the edge region. The frequently observed steep edge temperature gradients are found to depend as much on the variation in conductive and convective heat fluxes as on a reduction in χi,e. Inferred χi,eexp are compared with theoretical predictions.

[1]  A. Hubbard,et al.  Physics and scaling of the H-mode pedestal , 2000 .

[2]  T. Osborne,et al.  Ballooning mode stability for self-consistent pressure and current profiles at the H-mode edge , 1997 .

[3]  Weston M. Stacey.  Modelling the neutral density in the edge of the DIII-D plasma , 2000 .

[4]  S. Voskoboynikov,et al.  Characterization of the H-mode edge barrier at ASDEX Upgrade , 2005 .

[5]  Choong-Seock Chang,et al.  Numerical study of neoclassical plasma pedestal in a tokamak geometry , 2004 .

[6]  L. L. Lao,et al.  The Effect of Plasma Shape on H-Mode Pedestal Characteristics on DIII-D , 1999 .

[7]  Weston M. Stacey.  Edge pedestal structure , 2004 .

[8]  S. J. Wukitch,et al.  Measurements of the high confinement mode pedestal region on Alcator C-Mod , 1998 .

[9]  Ker-Chung Shaing,et al.  Effects of orbit squeezing on ion transport in the banana regime in tokamaks , 1992 .

[10]  W. Treutterer,et al.  Effect of Plasma Shape Variation on ELMs and H-Mode Pedestal Properties in ASDEX Upgrade , 2000 .

[11]  T. Petrie,et al.  Investigation of physical processes limiting plasma density in high confinement mode discharges on DIII-D , 1997 .

[12]  L. L. Lao,et al.  ELMs and constraints on the H-mode pedestal: peeling–ballooning stability calculation and comparison with experiment , 2004 .

[13]  X. Loozen,et al.  Predictive modelling of L and H confinement modes and edge pedestal characteristics , 2005 .

[14]  R. L. Miller,et al.  Magnetohydrodynamic stability of tokamak edge plasmas , 1998 .

[15]  R. J. Groebner,et al.  Scaling studies of the high mode pedestal , 1998 .

[16]  Weston M. Stacey,et al.  Investigation of edge pedestal structure in DIII-D (DoE Grant ER54538) , 2005 .

[17]  G. Porter,et al.  Detailed comparison of simulated and measured plasma profiles in the scrape-off layer and edge plasma of DIII-D , 2000 .

[18]  Adil Hassam,et al.  Three‐dimensional fluid simulations of the nonlinear drift‐resistive ballooning modes in tokamak edge plasmas , 1993 .

[19]  R. A. Hulse.  Numerical studies of impurities in fusion plasmas , 1983 .

[20]  E. W. Thomas,et al.  Deuterium atomic cross section uncertainties and molecular recycling effects in the divertor region of tokamaks , 1997 .

[21]  L. Lao,et al.  Modification of high mode pedestal instabilities in the DIII-D tokamak , 2000 .

[22]  P. C. Stangeby,et al.  Comparison of H-mode barrier width with a model of neutral penetration length , 2004 .

[23]  Weston M. Stacey,et al.  A framework for the development and testing of an edge pedestal model: Formulation and initial comparison with DIII-D data , 2003 .

[24]  T D Rognlien,et al.  Simulation of edge-plasma profiles and turbulence related to L-H transitions in tokamaks , 1999 .

[25]  Arnold H. Kritz,et al.  Models for the pedestal temperature at the edge of H-mode tokamak plasmas , 2002 .

[26]  H. Wilson,et al.  Access to second stability region for coupled peeling-ballooning modes in tokamaks , 1999 .

[27]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[28]  F. Romanelli,et al.  Anomalous thermal confinement in ohmically heated tokamaks , 1986 .

[29]  G. Corrigan,et al.  EDGE2D modelling of edge profiles obtained in JET diagnostic optimized configuration , 2004 .