Aachen PK 2003 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
P: Plasmaphysik
P 14: Basic Plasma Physics, Theory
P 14.1: Talk
Thursday, March 20, 2003, 11:30–11:50, FO2
Geodesic Acoustic Modes in TJ-K — •M. Ramisch1, K. Rahbarnia1, B. Scott2, and U. Stroth1 — 1Institut für Experimentelle und Angewandte Physik der Christian-Albrechts-Universität zu Kiel — 2Max Planck Institut für Plasmaphysik, Garching
Zonal flows (ZF) in toroidal plasmas come in two types: a low-frequency ZF and the geodesic acoustic mode (GAM). Both are homogeneous on a flux surface (kθ = k∥ = 0) but they differ in frequency: ωZF ≈ 0, ωGAM ∼ cs/R, where cs is the ion sound speed and R the major plasma radius.
Results from analyses of data obtained from the drift Alfvén turbulence simulation code DALF3 point to the mean poloidal flow being dominated by GAMs in toroidal plasma devices. It is shown that the shear flow of the GAMs contributes to a reduction in radial transport. The property ωGAM ∼ cs/R provides an experimental test for GAMs.
Numerical results are introduced and compared with data from emissive probes implimented in the low-temperature plasma of the torsatron TJ-K.