Dissipation of Alfven waves in solar coronal arches

The physical mechanism by which mechanical energy is delivered to and absorbed by the solar corona is discussed. A set of MHD equations for analyzing the slow evolution of the magnetic field and the fast time of Alfven waves is presented. Alfven wave dissipation is treated. It is shown that the slow motion of the feet of coronal arches leads to irregular magnetic fields and that Alfven waves propagating in the irregular magnetic structure are dissipated through filamentation of the wave packet that generates short scales necessary for efficient dissipation.