NONLINEARITY EFFECTS ON RESONANT ABSORPTION OF SURFACE ALFVEN WAVES IN INCOMPRESSIBLE PLASMAS

The resonant absorption of small amplitude surface Alfven waves is studied in nonlinear incompressible MHD for a viscous and resistive plasma. The reductive perturbation method is used to obtain the equation that governs the spatial and temporal behaviour of small amplitude nonlinear surface Alfven waves. Numerical solutions to this equation are obtained under the initial condition that at t = 0 the spatial variation is purely sinusoidal. The numerical results show that nonlinearity accelerates the wave damping due to resonant absorption. Resonant absorption is a more efficient wave damping mechanism than can be anticipated on the basis of linear theory.