Resonant absorption of kink MHD waves in twisted flux tubes with thick transitional layer

The effect of magnetic twist on the resonant absorption of propagating magnetohydrodynamic (MHD) waves in coronal flux tubes with thick transitional layer has been investigated. The flux tube is assumed to be a density enhancement in a zero beta plasma with twisted magnetic field. In the thin tube approximation a perturbation method is used to solve equations of motion analytically in all the regions of the tube including the transitional layer. The dispersion relation is solved numerically to investigate both the temporal and spatial damping of the kink MHD waves. We have introduced a symmetry of the MHD waves in the presence of magnetic twist which has not been discussed earlier, this symmetry allows us to study only forward waves. The efficiency of resonant absorption depends on the sign of the twist parameter. For negative values of the twist parameter resonant absorption becomes sufficiently effective, and for positive values of the twist parameter, especially for a thick transitional layer, resonant absorption becomes almost ineffective. For a specific twist parameter, resonant absorption is efficient for the waves in which the sign of their wave number is opposite to that of the twist parameter.