Resistive Drift-Alfvén Instability in a Cylindrical Plasma

Abstract

Linearized eigenmode equations governing resistive drift-Alfvén modes are derived by using the two-fluid model for a cylindrical plasma with a uniform longitudinal magnetic field. The local dispersion relation shows that the shear Alfvén wave couples with the unstable resistive drift wave due to the finite Larmor radius effect measured with the electron temperature. The eigenmode equations are solved by the shooting method in the cylindrical plasma. The eigenfunction of the drift-Alfvén instability is more localized at the edge region for the larger poloidal mode number m. The growth rate of the most unstable mode is independent of the plasma density. It decreases with the increase of electron pressure (electron temperature) for m≥q 9, although the electron pressure effect is weak for the low m modes. This behavior seems consistent with a theoretical model that the stabilization of drift-Alfvén wave induces the L (Low confinement)-H(High confinement) transition at the edge of tokamak plasma.