1. The systematic investigation of energetic-particle-driven geodesic acoustic mode channeling using MEGA code
- Author
-
Takeshi Ido, Hao Wang, Yasushi Todo, Yasuhiro Suzuki, and Masaki Osakabe
- Subjects
Physics ,EGAM profiles in the three-dimensional (3D) form ,Nuclear and High Energy Physics ,EGAM channeling ,energetic-particle-driven geodesic acoustic mode (EGAM) ,Plasma ,Condensed Matter Physics ,hybrid simulation code MEGA ,01 natural sciences ,010305 fluids & plasmas ,Computational physics ,Ion ,Large Helical Device ,energy transfer efficiency ,Physics::Plasma Physics ,Large Helical Device (LHD) plasmas ,0103 physical sciences ,Chirp ,Magnetohydrodynamic drive ,Pitch angle ,Magnetohydrodynamics ,010306 general physics ,Particle beam ,isotope effect - Abstract
Energetic-particle-driven geodesic acoustic modes (EGAMs) channeling in the Large Helical Device (LHD) plasmas are systematically investigated for the first time using MEGA code. MEGA is a hybrid simulation code for energetic particles interacting with a magnetohydrodynamic (MHD) fluid. In the present work, both the energetic particles and the bulk ions are described kinetically. The EGAM profiles in the three-dimensional form is illustrated. Then, EGAM channeling behaviors are analyzed under different conditions. During the EGAM activities without frequency chirping, EGAM channeling occurs in the linear growth stage but terminates in the decay stage after the saturation. During the EGAM activities with frequency chirping, EGAM channeling occurs continuously. Also, low-frequency EGAM makes the energy transfer efficiency (Eion/EEP) higher, and this is confirmed by changing the energetic particle pressure, energetic particle beam velocity, and energetic particle pitch angle. Moreover, higher bulk ion temperature makes the energy transfer efficiency higher. In addition, under a certain condition, the energy transfer efficiency in the deuterium plasma is lower than that in the hydrogen plasma.
- Published
- 2020
- Full Text
- View/download PDF