RMP ELM Suppression in DIII-D Plasmas with ITER Similar Shapes and Collisionalities

Journal Article · Tue Jan 01 00:00:00 EST 2008 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/48/2/024002· OSTI ID:1001312

Evans, T. E. ^[1]; Fenstermacher, M. E. ^[2]; Moyer, R. A. ^[3]; Osborne, T. H. ^[4]; Watkins, J. G. ^[5]; Gohil, P. ^[4]; Joseph, I. ^[3]; Schaffer, M. J. ^[1]; Baylor, Larry R ^[6]; Becoulet, M. ^[7]; Boedo, J. A. ^[3]; Burrell, K. H. ^[4]; DeGrassie, J. S. ^[1]; Finken, K. H. ^[8]; Jernigan, Thomas C ^[6]; Jakubowski, M. W. ^[8]; Lasnier, C. J. ^[2]; Lehnen, M. ^[9]; Leonard, A. W. ^[4]; Lonnroth, J. ^[10] ; Nardon, E. ^[7]; Parail, V. ^[11]; Schmitz, O. ^[9]; Unterberg, B. ^[8]; West, W. P. ^[1]

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1. General Atomics, San Diego
2. Lawrence Livermore National Laboratory (LLNL)
3. University of California, San Diego
4. General Atomics
5. Sandia National Laboratories (SNL)
6. ORNL
7. CEA Cadarache, St. Paul lex Durance, France
8. Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany
9. Forschungszentrum Julich, Julich, Germany
10. Association Euratom-Tekes, Finland
11. EURATOM / UKAEA, UK

Large Type-I edge localized modes (ELMs) are completely eliminated with small n = 3 resonant magnetic perturbations (RMP) in low average triangularity, = 0.26, plasmas and in ITER similar shaped (ISS) plasmas, = 0.53, with ITER relevant collisionalities ve 0.2. Significant differences in the RMP requirements and in the properties of the ELM suppressed plasmas are found when comparing the two triangularities. In ISS plasmas, the current required to suppress ELMs is approximately 25% higher than in low average triangularity plasmas. It is also found that the width of the resonant q95 window required for ELM suppression is smaller in ISS plasmas than in low average triangularity plasmas. An analysis of the positions and widths of resonant magnetic islands across the pedestal region, in the absence of resonant field screening or a self-consistent plasma response, indicates that differences in the shape of the q profile may explain the need for higher RMP coil currents during ELM suppression in ISS plasmas. Changes in the pedestal profiles are compared for each plasma shape as well as with changes in the injected neutral beam power and the RMP amplitude. Implications of these results are discussed in terms of requirements for optimal ELM control coil designs and for establishing the physics basis needed in order to scale this approach to future burning plasma devices such as ITER.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1001312
• Journal Information: Nuclear Fusion, Vol. 48, Issue 2; ISSN 0029--5515
• Country of Publication: United States
• Language: English