Experimental Basic Physics Study of Zonal Flows
Author: Amiya K Sen
Requested Type: Poster Only
Submitted: 2006-12-18 13:54:43
Co-authors: V.Sokolov and X.Wei
Contact Info:
Plasma Physics Laboratory, Columbia University
1300 Mudd, 500 West 120th Stre
New York, NY 10027
USA
Abstract Text:
The role of self-generated zonal flows (ZF) in transport regulation in magnetic confinement devices via its shear is a potent concept and a physics issue [P.H. Diamond, S-I Itoh, K.Itoh and T.S.Hahm, Plasma Phys.Controlled Fusion 47, R35 (2005)]. A basic physics experimental study of ZF associated with ITG (ion temperature gradient) drift modes has been performed in the Columbia Linear Machine [R. Scarmozzino, A.K. Sen, and G.A. Navratil, Phys.Rev.Lett. 57, 1729 (1986).]. The difficult problem of detection of ZF has been solved via a novel diagnostic using the paradigm of FM (frequency modulation) in radio transmission. Using this and Discrete Short Time Fourier Transform, we find a power spectrum peak at ITG (‘carrier’) frequency of and FM sidebands at frequency of . We have definitively identified ZF with azimuthal (poloidal) and axial (toroidal) symmetry and radially inhomogeneous flow structures in cylindrical plasmas. However, the stabilizing effect of ZF shear appears to be small and no significant isotopic effects are observed.
Characterization: A5,E4
Comments:
