Kinetic effects on collisionless high-n ballooning modes and ion temperature gradient modes in a model helical geometry

An electromagnetic approach is applied to unstable modes in the ion branch for a model helical geometry. Such pure kinetic effects as the stabilization of high-n ballooning modes due to finite Larmor radius, and the suppression of ion temperature gradient modes, when the plasma-β is increased, are studied and new results from comparing these effects in two-dimensional (i. e. tokamak) and three-dimensional (i. e. model helical) geometry are reported. (orig.)