Geodesic Acoustic Modes and Alfvén Continuum in Plasma Columns with Rotation

Abstract

In the context of the current research in controlled nuclear fusion, mechanisms that allow the existence of improved regimes of confinement (or H mode) have been drawing much attention. This kind of regime, characterized by an effective anomalous transport self-control, is triggered by mechanisms of suppression of intabilities, associated to geodesic acoustic modes (GAMs) and zonal flows (ZF). In studying these modes with realistic plasma configurations, effects due to the plasma column rotation (both poloidal and toroidal) should be taken into account. These effects, object of several studies in recent years, can substantially modify the modes frequency and besides, it may introduce new frequency branches associated to the modified dispertion relation. This project aims to study the column rotation effects on GAMs, ZF and the Alfvén Continuum. The latter may have a frequency coinciding with the GAMs one. We intend to analyze configurations with realistic experimental parameters, with a special focus on TCABR and JET tokamaks. Both fluid and kinetic descriptions will be considered. The work will be mostly analytical however, numerical works will be eventually performed.