Greifswald 2009 – scientific programme

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P: Fachverband Plasmaphysik

P 16: Poster: Magnetischer Einschluss

P 16.1: Poster

Wednesday, April 1, 2009, 17:30–19:30, Foyer des IfP

Collisional zonal-flow damping in an impure tokamak plasma — •Stefanie Braun and Per Helander — MPI für Plasmaphysik, Wendelsteinstr. 1, 17491 Greifswald

So-called zonal flows are known to play a significant role in tokamak plasma confinement by reducing the level of turbulent transport. It is shown that the presence of highly charged impurity ions strongly increases the collisional damping of these flows. A formula for the zonal-flow damping time is derived, which indicates that the damping is enhanced approximately by a factor Z_eff. In the case of large aspect ratio, the enhancement is considerably larger.