April 15-17

Abstract Details

files Add files

status:file name:submitted:by:
approvedabstract.pdf2019-02-25 05:13:05Zhaoyang Liu

Abstracts

Author: Zhaoyang Liu
Requested Type: Poster
Submitted: 2019-02-18 01:42:53

Co-authors: Y.Z.Zhang, S.M.Mahajan, T.Xie, A.D.Liu, C.Zhou, T.Lan, J.L.Xie, H.Li, G.Zhuang, and W.D.Liu

Contact Info:
University of Science and Technology of China
Huangshan road
Hefei, Anhui   230026
China

Abstract Text:
Through a carefully designed numerical experiment, we demonstrate that a transition between two distinct phases of energy concentration in a zonal flow-drift wave system (caviton and instanaton) may play a key role in the intermittent excitation of geodesic acoustic mode (GAM) that are observed in tokamaks. The two energy structures - the caviton, a slowly breathing spatial local structure of ‘negative’ energy, and the instanton, a fine radial structure of short lifetime in rapid propagation, were recently identified in [Zhang Y.Z., Liu Z.Y., Xie T., Mahajan S.M., and Liu J. 2017 Physics of Plasmas 24, 122304]. The transition (decay) from the former to the latter is triggered by a rapid zero-crossing of radial group velocity of drift wave and is found to be strongly correlated with the GAM onset. Many features peculiar to intermittent GAMs, observed in real machines, are identified in the numerical experiment; the results will be displayed in figures and in a movie.

Comments: