H-mode pedestal characteristics, ELMs, and energy confinement in ITER shape discharges on DIII-D [electronic resource]
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| Online Access: |
Online Access |
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| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Washington, D.C. : Oak Ridge, Tenn. :
United States. Dept. of Energy. Office of Energy Research ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy,
1997.
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| Abstract: | 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. |
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| Item Description: | Published through the Information Bridge: DOE Scientific and Technical Information. 12/01/1997. "GA--A22733" "CONF-9709100--" "DE98001905" US/Japan workshop on H-mode physics and 6th H-mode workshop, Kloster Seeon (Germany), 22-24 Sep 1997. Miller, R.L.; Thomas, D.M.; Osborne, T.H.; Leonard, A.W.; Waltz, R.E.; Porter, G.D.; Groebner, R.J.; Lao, L.L.; Maingi, R. General Atomics, San Diego, CA (United States);Oak Ridge National Lab., TN (United States);Lawrence Livermore National Lab., CA (United States)] |
| Physical Description: | 15 p. |