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 (Er) 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 Ti profile.
- Research Organization:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Contributing Organization:
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, NJ 08543, USA
- Grant/Contract Number:
- AC02-09CH11466; FC02-04ER54698; FG02-07ER54917; AC05-00OR22725
- OSTI ID:
- 1308447
- Alternate ID(s):
- OSTI ID: 1263685; OSTI ID: 1371847; OSTI ID: 1572197
- Journal Information:
- Plasma Physics and Controlled Fusion, Vol. 58, Issue 8; ISSN 0741-3335
- Publisher:
- IOP ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Main ion and impurity edge profile evolution across the L- to H-mode transition on DIII-D
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journal | August 2018 |
Active spectroscopy measurements of the deuterium temperature, rotation, and density from the core to scrape off layer on the DIII-D tokamak (invited)
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journal | October 2018 |
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