Connection between plasma response and resonant magnetic perturbation (RMP) edge localized mode (ELM) suppression in DIII-D [Connection between plasma response and RMP ELM suppression in DIII-D]
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- General Atomics, San Diego, CA (United States)
Calculations of the plasma response to applied non-axisymmetric elds in several DIII-D discharges show that predicted displacements depend strongly on the edge current density. This result is found using both a linear two- uid-MHD model (M3D-C1) and a nonlinear ideal-MHD model (VMEC). Furthermore, it is observed that the probability of a discharge to be edge localized mode (ELM)-suppressed is most closely related to the edge current density, as opposed to the pressure gradient. It is found that discharges with stronger kink-response are closer to the peeling-ballooning stability limit in ELITE simulations and eventually cross into the unstable region, causing ELMs to reappear. Thus for e ective ELM suppression, the RMP has to hold back the plasma from generating a large kink response, associated with ELM instability. Experimental observations are in agreement with the nding; discharges which have a strong kink response in the MHD simulations show ELMs or ELM mitigation during the RMP phase of the experiment while discharges with small kink response in the MHD simulations are fully ELM suppressed in the experiment by the applied resonant magnetic perturbation. The results are cross-checked against modeled 3-D ideal MHD equilibria, using the VMEC code. The procedure to construct optimal 3-D equilibria for diverted H-mode discharges using VMEC is presented. It is found that the kink displacements in VMEC scale with the edge current density, similar to M3D-C1, but the displacements are smaller. A direct correlation of the ux surface displacements to the bootstrap current is shown.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); USDOE Advanced Research Projects Agency - Energy (ARPA-E); USDOE Office of Nuclear Energy (NE)
- Grant/Contract Number:
- AC05-00OR22725; FC02-04ER54698
- OSTI ID:
- 1265646
- Alternate ID(s):
- OSTI ID: 1238958; OSTI ID: 1356345
- Journal Information:
- Plasma Physics and Controlled Fusion, Vol. 57, Issue 10; ISSN 0741-3335
- Publisher:
- IOP ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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