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Title: Improved kinetic neoclassical transport calculation for a low-collisionality QH-mode pedestal

The role of neoclassical, anomalous and neutral transport to the overall H-mode pedestal and scrape-off layer (SOL) structure in an ELM-free QH-mode discharge on DIII-D is explored using XGC0, a 5D full-f multi-species particle-in-cell drift-kinetic solver with self-consistent neutral recycling and sheath potentials. The work in this paper builds on previous work aimed at achieving quantitative agreement between the flux-driven simulation and the experimental electron density, impurity density and orthogonal measurements of impurity temperature and flow profiles. Improved quantitative agreement is achieved by performing the calculations with a more realistic electron mass, larger neutral density and including finite-Larmor-radius corrections self-consistently in the drift-kinetic motion of the particles. Consequently, the simulations provide stronger evidence that the radial electric field (E-r) in the pedestal is primarily established by the required balance between the loss of high-energy tail main ions against a pinch of colder main ions and impurities. The kinetic loss of a small population of ions carrying a large proportion of energy and momentum leads to a separation of the particle and energy transport rates and introduces a source of intrinsic edge torque. Ion orbit loss and finite orbit width effects drive the energy distributions away from Maxwellian, and describe themore » anisotropy, poloidal asymmetry and local minimum near the separatrix observed in the T-i profile.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [1] ;  [2] ;  [1]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. General Atomics, San Diego, CA (United States)
Publication Date:
OSTI Identifier:
1308447
Grant/Contract Number:
AC02-09CH11466; FC02-04ER54698; FG02-07ER54917; AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Volume: 58; Journal Issue: 8; Journal ID: ISSN 0741-3335
Publisher:
IOP Science
Research Org:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS tokamak; pedestal; electric field; transport; kinetic neoclassical; ion orbit loss