Improved kinetic neoclassical transport calculation for a low-collisionality QH-mode pedestal [electronic resource]
Tokamak; Pedestal; Electric Field; Transport; Kinetic Neoclassical; Ion Orbit Loss.
Saved in:
| Online Access: |
Online Access (via OSTI) |
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| Corporate Author: | |
| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Washington, D.C. : Oak Ridge, Tenn. :
United States. Department of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Department of Energy,
2016.
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| Subjects: |
| Summary: | Tokamak; Pedestal; Electric Field; Transport; Kinetic Neoclassical; Ion Orbit Loss. |
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| Abstract: | 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<sub>r</sub>) 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 the anisotropy, poloidal asymmetry and local minimum near the separatrix observed in the T<sub>i</sub> profile. |
| Item Description: | Published through SciTech Connect. 07/15/2016. Plasma Physics and Controlled Fusion 58 8 ISSN 0741-3335 AM. D. J. Battaglia; K. H. Burrell; C. S. Chang; J. S. deGrassie; B. A. Grierson; R. J. Groebner; R. Hager. |
| Physical Description: | Article No. 085009 : digital, PDF file. |