Energetic particle modes of q = 1 high-order harmonics in tokamak plasmas with monotonic weak magnetic shear

Journal Article · Mon Apr 24 00:00:00 EDT 2017 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4981935· OSTI ID:1378441

Ren, Zhen-Zhen  ^[1]; Wang, Feng ^[1]; Fu, G. Y. ^[2]; Shen, Wei ^[3]; Wang, Zheng-Xiong ^[1]

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1. Dalian Univ. of Technology, Dalian (China). Key Lab. of Materials Modification by Laser, Ion and Electron Beams, School of Physics
2. Zhejiang Univ., Hangzhou (China). Inst. for Fusion Theory and Simulation and Dept. of Physics; Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
3. Chinese Academy of Sciences (CAS), Hefei (China). Inst. of Plasma Physics

Linear and nonlinear simulations of high-order harmonics q=1 energetic particle modes excited by trapped energetic particles in tokamaks are carried out using kinetic/magnetohydrodynamic hybrid code M3D-K. It is found that with a flat safety factor profile in the core region, the linear growth rate of high-order harmonics (m=n>1) driven by energetic trapped particles can be higher than the m/n=1/1 component. The high m=n>1 modes become more unstable when the pressure of energetic particles becomes higher. Moreover, it is shown that there exist multiple resonant locations satisfying different resonant conditions in the phase space of energetic particles for the high-order harmonics modes, whereas there is only one precessional resonance for the m/n=1/1 harmonics. The fluid nonlinearity reduces the saturation level of the n=1 component, while it hardly affects those of the high n components, especially the modes with m=n=3,4. The frequency of these modes does not chirp significantly, which is different with the typical fishbone driven by trapped particles. Lastly, in addition, the flattening region of energetic particle distribution due to high-order harmonics excitation is wider than that due to m/n=1/1 component, although the m/n=1/1 component has a higher saturation amplitude.

• Research Organization: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: USDOE; National Magnetic Confinement Fusion Science Program of China; Fundamental Research Funds for the Central Universities
• Grant/Contract Number: 2013GB111000; 2014GB124000; 11322549; 11605245; 11675038; DUT15YQ103
• OSTI ID: 1378441
• Journal Information: Physics of Plasmas, Vol. 24, Issue 5; ISSN 1070-664X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Particle distribution functions
Magnetohydrodynamics
Tokamaks
Chirping
Hybrid methods