Evidence of perpendicular flow bifurcation at the onset of ELM-crash suppression
- Title
- Evidence of perpendicular flow bifurcation at the onset of ELM-crash suppression
- Authors
- LEE, Jaehyun; JEON, YoungMu; In, Yongkyoon; YUN, GUNSU; KIM, Minwoo; CHOI, Minjun; PARK, Gunyoung; PARK, Hyeon K
- Date Issued
- 2017-10-25
- Publisher
- American Physical Society
- Abstract
- The evidence of perpendicular electron flow (v ⊥,e
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) bifurcation at the onset of ELM-crash suppression has been measured using electron cyclotron emission imaging (ECEI) system [1] for the first time in KSTAR. The ECEI has shown that (1) resonant magnetic perturbation (RMP) enhances small scale turbulent fluctuations in the edge toward the ELM-crash suppression phase, (2) the induced turbulence regulates growth of the ELM filament via nonlinear interaction between them [2]. Cross spectra and correlation analysis among the ECEI channels revealed that the ELM crashes get suppressed along with a rapid reduction of v ⊥,e
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close to zero (small but finite value) together with decrease of its shear. The v ⊥,e ∼ 0 km/s
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is sustained during the ELM-crash suppression even under a large variation of RMP current and external torque and when this condition is violated, ELM crashes are reappeared. [1] G.S. Yun et al., Rev. Sci. Instrum., 81 (2010) 10D930 [2] J. Lee et al., Phys. Rev. Lett., 117 (2016) 075001
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/45740
- Article Type
- Conference
- Citation
- 59th Annual Meeting of the APS Division of Plasma Physics, page. NO04 - 00005, 2017-10-25
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