Results for resistive compressible flow ballooning modes in a large aspect ratio expansion

Based on an eikonal approach and the corresponding expansion in the inverse toroidal mode number 1/n large aspect ratio expanded equations for linear resistive, compressible ballooning modes including toroidal, sheared flow are derived. Limitations of this formalism leading to a nonexponential time behavior of perturbed quantities are discussed and a procedure for the extraction of an effective growth rate is offered. The ballooning equations are solved numerically for parameter values corresponding to a typical ASDEX tokamak [Nucl. Fusion 25, 705 (1985)] high beta discharge. The importance of the flow shear on the stabilization of ballooning modes compared to purely rigid rotation is demonstrated. Furthermore, results for perturbed quantities in physical space are given and their dependence on flow is investigated.