H-mode pedestal characteristics, ELMs, and energy confinement in ITER shape discharges on DIII-D
- General Atomics, San Diego, CA (United States)
- Oak Ridge National Lab., TN (United States)
- Lawrence Livermore National Lab., CA (United States)
The H-mode confinement enhancement factor, H, is found to be strongly correlated with the height of the edge pressure pedestal in ITER shape discharges. In discharges with Type I ELMs the pedestal pressure is set by the maximum pressure gradient before the ELM and the width of the H-mode transport barrier. The pressure gradient before Type I ELMs is found to scale as would be expected for a stability limit set by ideal ballooning modes, but with values significantly in excess of that predicted by stability code calculations. The width of the H-mode transport barrier is found to scale equally well with pedestal P(POL)(2/3) or B(POL)(1/2). The improved H value in high B(POL) discharges may be due to a larger edge pressure gradient and wider H-mode transport barrier consistent with their higher edge ballooning mode limit. Deuterium puffing is found to reduce H consistent with the smaller pedestal pressure which results from the reduced barrier width and critical pressure gradient. Type I ELM energy loss is found to be proportional to the change in the pedestal energy.
- Research Organization:
- General Atomics, San Diego, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lawrence Livermore National Lab., CA (United States)]
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114; AC05-96OR22464; W-7405-ENG-48
- OSTI ID:
- 634076
- Report Number(s):
- GA-A22733; CONF-9709100-; ON: DE98001905; TRN: 98:009759
- Resource Relation:
- Conference: US/Japan workshop on H-mode physics and 6th H-mode workshop, Kloster Seeon (Germany), 22-24 Sep 1997; Other Information: PBD: Dec 1997
- Country of Publication:
- United States
- Language:
- English
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