Electrostatic ion-temperature-gradient modes and anomalous transports in a collision-dominated plasma

By employing a two fluid model, a set of equations for ion pressure gradient driven low-frequency (in comparison with the ion-gyrofrequency) electrostatic waves in a collisional magnetoplasma has been derived. The equations exhibit a coupling between the electrostatic potential, the parallel ion velocity and ion-temperature perturbations. In the linear limit, a new dispersion relation has been derived and analyzed numerically to demonstrate the existence of ion-temperature-gradient driven drift-dissipative modes. Since in a highly collisional plasma there is a departure from the Boltzmann electron response, there appears anomalous particle and ion-energy transports due to nonthermal fluctuations. Taking some typical tokamak parameters, the transport coefficients are numerically depicted for maximally growing drift wave fluctuations. The results of our investigation are useful for the understanding of fluctuation driven transports in tokamak edges in which collisions are dominant. (orig.)