Kinetic theory of the ion-temperature-gradient-driven mode in the long wavelength limit

The stability of the ion-temperature-gradient-driven mode in the long wavelength limit is investigated by retaining the kinetic effects associated with the ion transit frequency. The complete trapped electron dynamics is also considered. The toroidal branch is weakly affected by the trapped electron dynamics while the slablike branch is more strongly affected by trapped electrons. The implications of these results for the understanding of the improved confinement regimes observed in the presence of peaked density profiles is also discussed.