ISI Citation Indexes
Help

General Search Results--Full Record
Article 83 of 99 Previous record Next record Summary List
Explanation

GEOMETRICAL AND PROFILE EFFECTS ON TOROIDICITY AND ELLIPTICITY INDUCED ALFVEN EIGENMODES
VILLARD L, FU GY
NUCLEAR FUSION
32 (10): 1695-1713 OCT 1992

Document type: Article    Language: English    Cited References: 28    Times Cited: 23   

Abstract:
The wave structures, eigenfrequencies and damping rates of toroidicity and ellipticity induced Alfven eigenmodes (TAEs, EAEs) of low toroidal mode numbers (n) are calculated for various axisymmetric ideal MHD equilibria with the global wave finite element code LION. The importance of the safety factor (q) and density (rho) profiles on the continuum damping rates is analysed. For realistic profiles, several continuum gaps exist in the plasma discharge. Frequency misalignment of these gaps yields continuum damping rates gamma/omega of the order of a few per cent. Finite poloidal beta lowers the TAE eigenfrequency. For beta values below the Troyon limit, the TAE enters the continuum and can thus be stabilized. Finite elongation allows the EAE to exist, but triangularity can have a stabilizing effect through coupling with the continuum. The localization of TAE and EAE eigenfunctions is found to increase with the shear and with n. Therefore, large shear, through enhanced Landau and collisional damping, is a stabilizing factor for TAEs and EAEs.

KeyWords Plus:
LOW-FREQUENCY, TOKAMAK, PLASMA, EXCITATION, SPECTRUM, WAVES, COLD

Addresses:
VILLARD L, ECOLE POLYTECH FED LAUSANNE,ASSOC EURATOM CONFEDERAT SUISSE,CTR RECH PHYS PLASMAS,CH-1007 LAUSANNE,SWITZERLAND

Publisher:
INT ATOMIC ENERGY AGENCY, VIENNA

IDS Number:
JY298

ISSN:
0029-5515


Article 83 of 99 Previous record Next record Summary List


Acceptable Use Policy

Copyright © 2001 Institute for Scientific Information