Effect of impurities on collisional zonal flow damping in tokamaks

S Braun, P Helander, E A Belli, J Candy
2009 Plasma Physics and Controlled Fusion  
It is shown that the presence of highly charged impurity ions strongly increases the collisional damping of zonal flows in a low-collisionality tokamak plasma. A formula for the zonal-flow damping time is derived, which indicates that the damping is enhanced approximately by a factor Z eff . If the aspect ratio is large, the enhancement is significantly larger. The zonal-flow damping time is also the time which the poloidal plasma rotation needs to respond to a sudden change in the pressure
more » ... in the pressure gradients.
doi:10.1088/0741-3335/51/6/065011 fatcat:fpa53e3anjcpveio6sbmq6v7g4