Transport processes and instabilities in magnetically confined plasmas with Tsub(i perpendicular) approximately Tsub(e perpendicular)

A series of instabilities and transport processes relevant to high-temperature magnetically confined plasmas with almost equal electron and ion transverse temperatures are presented. These plasma regimes have been realized either as a result of high electron-ion collision rates (high density) or of the excitation of current-driven modes above the ion cyclotron frequency (low density). In the high density regime a model for the anomalous energy diffusion that invokes the excitation of current-driven drift modes below the ion cyclotron frequency is described considering in particular a degree of collisionality for which the current-carrying electron distribution is significantly affected by magnetic trapping. It is also shown that, in this regime, for proper combination of high densities and high temperatures, the stability of the m0=1 internal kink modes is considerably improved by the simultaneous effects of electrical resistivity, finite ion gyroradius, finite electron drift wave frequency, and ion-ion collisions under realistic conditions. In the low density regime, a combination of Fokker-Planck and particle codes is used to study the positive slope formation and the energy transfer to the ions, resulting from the excitation of modes with frequencies near the ion plasma frequency. (author)