title: Properties of geodesic acoustic modes and the relation to density fluctuations.
abstract: The geodesic acoustic mode (GAM) is a high frequency branch of zonal flows, which is observed in toroidal plasmas. Because of toroidal curvature effects, density fluctuations are excited, which are investigated with the O-mode correlation reflectometer at TEXTOR. This Letter reports on the poloidal distribution of GAM induced density fluctuation and compares them with theoretical predictions. The influence of the GAM flows on the ambient turbulence is studied, too.
authors.affiliation: Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, D-52425 Jülich, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Krämer-Flecken
authors.forename: S
authors.initials: S
authors.lastname: Soldatov
authors.forename: H R
authors.initials: HR
authors.lastname: Koslowski
authors.forename: O
authors.initials: O
authors.lastname: Zimmermann