Nonlinear behaviour of resistive drift-Alfvén mode is described by a three-field model composed of vorticity equation, Ohm's law and continuity equation. Resistive drift-Alfvén instabilities occur in the cylindrical plasma where both resistivity and plasma β value are finite. The resistive drift-Alfvén instabilities assuming single helicity generate poloidal sheared flow via the Reynolds stress by nonlinear mode couplings. The poloidal sheared flow stabilizes several unstable modes including the most unstable mode and leads to saturation of the nonlinear resistive drift-Alfvén modes. It is noted that some harmonics are destabilized by this flow. The level of magnetic fluctuations is much smaller than that due to density and electrostatic potential fluctuations. Particle flux due to the magnetic fluctuations is also extremely small compared to that due to electrostatic fluctuations. However, it is shown that the effect of magnetic fluctuations on the poloidal flow is significant. The magnetic fluctuations play a role of suppressing the poloidal flow drive by convective nonlinearity.
Nonlinear evolution of magnetic island in a sheared magnetic field with uniform plasma background