Studies of high-{delta} (baffled) and low-{delta} (open) pumped divertor operation on DIII-D
- Lawrence Livermore National Lab., CA (United States)
- General Atomics, San Diego, CA (United States); and others
The authors report new experimental results with the RDP-OB (Radiative Divertor Project-outer baffle) and cryopump in both upper single-null (USN) and double-null (DN) ELMing H-mode discharges. The baffled divertor reduced the core ionization ({approximately}2--2.5{times}), in reasonable agreement with predictions from UEDGE/DEGAS modeling ({approximately}3.75{times}). The upper cryopump achieved density control of n{sub e}/n{sub gw} {approximately} 0.22 (line density/Greenwald density) with Z{sub eff} {approximately} 2 in high-{delta} plasmas. The measured exhaust is comparable to the lower pump, except at lower core electron densities (n{sub e} < 5 {times} 10{sup 19} m{sup {minus}3}). Efficient impurity exhaust was obtained with deuterium SOL flow. Preliminary experiments with DN operation has shown that the particle exhaust to the upper pump depends on the up/down magnetic balance. Preliminary experiments indicate that the DN exhaust is roughly 40--50% of the USN exhaust at n{sub e} {approximately} 4 {times} 10{sup 19} m{sup {minus}3}.
- Research Organization:
- General Atomics, San Diego, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of California, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114; AC05-96OR22464; AC04-94AL85000; FG03-95ER54294; W-7405-ENG-48
- OSTI ID:
- 639804
- Report Number(s):
- GA-A22878; CONF-980560-; ON: DE98006223; TRN: 98:007945
- Resource Relation:
- Conference: 13. international conference on plasma surface interactions, San Diego, CA (United States), 18-22 May 1998; Other Information: PBD: Aug 1998
- Country of Publication:
- United States
- Language:
- English
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