The stability of zonal flows in finite beta tokamak edge plasmas

The generation of zonal flow in finite beta plasmas is an active area of research. We have developed a time-dependent code to investigate the stability of zonal flows in finite beta plasmas. The code can investigate different profiles of the zonal flow as well as the effects of magnetic shear. The focus of the investigation will be tokamak edge plasmas where finite beta effects are enhanced by steep pressure gradients and high safety factor q. We will present results of the stability of the zonal flows as a function of the two key dimensionless parameters, the classical ideal ballooning stability parameter and the diamagnetic parameter. The relevance of this study to edge transport will be discussed.