Results from core-edge experiments in high Power, high performance plasmas on DIII-D

Journal Article · Sat Dec 24 00:00:00 EST 2016 · Nuclear Materials and Energy

DOI:https://doi.org/10.1016/j.nme.2016.10.029· OSTI ID:1474338

Petrie, T. W.  ^[1]; Fenstermacher, M. E. ^[2]; Holcomb, C. T. ^[2]; Osborne, T. H. ^[1]; Allen, S. L. ^[2]; Ferron, J. R. ^[1]; Guo, H. Y. ^[1]; Lasnier, C. J. ^[2]; Leonard, A. W. ^[1]; Luce, T. C. ^[1]; Makowski, M. A. ^[2]; McLean, A. G. ^[2]; Pace, D. C.  ^[1]; Solomon, W. M. ^[1]; Turco, F. ^[3]; VanZeeland, M. A. ^[1]; Watkins, J. G. ^[4]

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1. General Atomics, San Diego, CA (United States)
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
3. Columbia Univ., New York, NY (United States)
4. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Here, significant challenges to reducing divertor heat flux in highly powered near-double null divertor (DND) hybrid plasmas, while still maintaining both high performance metrics and low enough density for application of RF heating, are identified. For these DNDs on DIII-D, the scaling of the peak heat flux at the outer target (q_⊥^P) ∝ [P_SOL x I_P]^0.92 for P_SOL = 8-19 MW and I_P = 1.0–1.4 MA, and is consistent with standard ITPA scaling for single-null H-mode plasmas. Two divertor heat flux reduction methods were tested. First, applying the puff-and-pump radiating divertor to DIII-D plasmas may be problematical at high power and H98 (≥ 1.5) due to improvement in confinement time with deuterium gas puffing which can lead to unacceptably high core density under certain conditions. Second, q_⊥^P for these high performance DNDs was reduced by ≈35% when an open divertor is closed on the common flux side of the outer divertor target (“semi-slot”) but also that heating near the slot opening is a significant source for impurity contamination of the core.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Contributing Organization: Lawrence Livermore National Laboratory, Livermore, California, USA Columbia University, New York, New York, USA Sandia National Laboratories, Albuquerque, New Mexico, USA
• Grant/Contract Number: AC52-07NA27344; FC02-04ER54698
• OSTI ID: 1474338
• Alternate ID(s): OSTI ID: 1372094
• Report Number(s): LLNL-JRNL-752185; 930435
• Journal Information: Nuclear Materials and Energy, Vol. 12, Issue C; ISSN 2352-1791
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DIII-D
divertor geometry
gas injection and fueling
impurity sources
power deposition