This title appears in the Scientific Report :
2005
Please use the identifier:
http://hdl.handle.net/2128/1898 in citations.
Please use the identifier: http://dx.doi.org/10.1088/0029-5515/45/7/007 in citations.
Suppression of large edge localized modes with edge resonant magnetic fields in high confinement DIII-D plasmas
Suppression of large edge localized modes with edge resonant magnetic fields in high confinement DIII-D plasmas
Large sub-millisecond heat pulses due to Type-I edge localized modes (ELMs) have been eliminated reproducibly in DIII-D for periods approaching nine energy confinement times (tau(E)) with small dc currents driven in a simple magnetic perturbation coil. The current required to eliminate all but a few...
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Personal Name(s): | Evans, T. E. |
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Moyer, R. A. / Watkins, J. G. / Osborne, T. H. / Thomas, P. R. / Bécoulet, M. / Boedo, J. A. / Doyle, E. J. / Fenstermacher, M. E. / Finken, K. H. / Groebner, R. J. / Groth, M. / Harris, J. H. / Jackson, G. L. / La Haye, R. J. / Lasnier, C. J. / Masuzaki, S. / Ohyabu, N. / Pretty, D. G. / Reimerdes, H. / Rhodes, T. L. / Rudakov, D. L. / Schaffer, M. J. / Wade, M. R. / Wang, G. / West, W. P. / Zeng, L. | |
Contributing Institute: |
Institut für Plasmaphysik; IPP |
Published in: | Nuclear fusion, 45 (2005) S. 595 - 607 |
Imprint: |
Vienna
IAEA
2005
|
Physical Description: |
595 - 607 |
DOI: |
10.1088/0029-5515/45/7/007 |
Document Type: |
Journal Article |
Research Program: |
Kernfusion und Plasmaforschung |
Series Title: |
Nuclear Fusion
45 |
Subject (ZB): | |
Link: |
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Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1088/0029-5515/45/7/007 in citations.
Large sub-millisecond heat pulses due to Type-I edge localized modes (ELMs) have been eliminated reproducibly in DIII-D for periods approaching nine energy confinement times (tau(E)) with small dc currents driven in a simple magnetic perturbation coil. The current required to eliminate all but a few isolated Type-l ELM impulses during a coil pulse is less than 0.4% of plasma current. Based on magnetic field line modelling, the perturbation fields resonate with plasma flux surfaces across most of the pedestal region (0.9 <= psi(N) <= 1.0) when q(95) = 3.7 +/- 0.2, creating small remnant magnetic islands surrounded by weakly stochastic field lines. The stored energy, beta(N), H-mode quality factor and global energy confinement time are unaltered by the magnetic perturbation. Although some isolated ELMs occur during the coil pulse, long periods free of large Type-l ELMs (Delta t > 4-6 tau(E)) have been reproduced numerous times, on multiple experimental run days in high and intermediate triangularity plasmas, including cases matching the baseline ITER scenario 2 flux surface shape. In low triangularity, lower single null plasmas, with collisionalities near that expected in ITER, Type-l ELMs are replaced by small amplitude, high frequency Type-II-like ELMs and are often accompanied by one or more ELM-free periods approaching 1-2 tau(E). Large Type-I ELM impulses represent a severe constraint on the survivability of the divertor target plates in future burning plasma devices. Results presented in this paper demonstrate that non-axisymmetric edge magnetic perturbations provide a very attractive development path for active ELM control in future tokamaks such as ITER. |