Generation of Geodesic Acoustic Modes and Zonal Flows by transport modulations

It is shown that Geodesic Acoustic Modes can be generated by modulations of the anomalous plasma transport. This mechanism is related to the Stringer spin-up and occurs as a result of the compressibility of the anomalous fluxes inducing pressure perturbation and subsequent radial current. The contribution of the transport modulations to the GAM growth rate is compared with the Reynolds stress drive. The generation of Zonal Flows due to the Reynolds stress and transport modulations mechanisms is also discussed..