Rippling and drift instabilities in the straight cylinder tokamak

It is shown that the electron and ion diamagnetic drifts stabilize the rippling mode in the straight cylindrical Tokamak model. Parallel electron heat conduction is further stabilizing if the parameter etasub(e)=dlnTsub(e)/dlnN is positive. This has as consequence that the mode does not survive at temperatures exceeding, typically, 50 eV for standard values of magnetic field and density. The collisional drift wave is found to be always stable even when the effect of the Tokamak current is included in the calculation. (author)