Nonlinear hybrid simulation of internal kink with beam ion effects in DIII-D

Journal Article · Wed Apr 15 04:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4917341· OSTI ID:22408318

Shen, Wei; Sheng, Zheng-Mao ^[1]; Fu, G. Y.; Tobias, Benjamin ^[2]; Zeeland, Michael Van ^[3]; Wang, Feng ^[4]

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1. Department of Physics, Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)
2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)
3. General Atomics, San Diego, California 92186-5608 (United States)
4. School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116024 (China)

In DIII-D sawteething plasmas, long-lived (1,1) kink modes are often observed between sawtooth crashes. The saturated kink modes have two distinct frequencies. The mode with higher frequency transits to a fishbone-like mode with sufficient on-axis neutral beam power. In this work, hybrid simulations with the global kinetic-magnetohydrodynamic (MHD) hybrid code M3D-K have been carried out to investigate the linear stability and nonlinear dynamics of the n = 1 mode with effects of energetic beam ions for a typical DIII-D discharge where both saturated kink mode and fishbone were observed. Linear simulation results show that the n = 1 internal kink mode is unstable in MHD limit. However, with kinetic effects of beam ions, a fishbone-like mode is excited with mode frequency about a few kHz depending on beam pressure profile. The mode frequency is higher at higher beam power and/or narrower radial profile consistent with the experimental observation. Nonlinear simulations have been performed to investigate mode saturation as well as energetic particle transport. The nonlinear MHD simulations show that the unstable kink mode becomes a saturated kink mode after a sawtooth crash. With beam ion effects, the fishbone-like mode can also transit to a saturated kink mode with a small but finite mode frequency. These results are consistent with the experimental observation of saturated kink mode between sawtooth crashes.

• OSTI ID: 22408318
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 4 Vol. 22; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COMPUTERIZED SIMULATION
DOUBLET-3 DEVICE
ION BEAMS
KHZ RANGE
MAGNETOHYDRODYNAMICS
NEUTRAL-PARTICLE TRANSPORT
NONLINEAR PROBLEMS
PLASMA
SAWTOOTH OSCILLATIONS