Energy dissipation mechanisms in the solar corona

Present ideas concerning the electric heating of the solar corona are reviewed. More detailed consideration is given to the dissipation of MHD waves in strong horizontal gradients of the Alfven velocity. Then the evolution of dc currents in the solar corona is considered. Some theories aiming at the evaluation of the net rate of energy dissipation by such mechanisms are described. A short account is given of a recent analytical study based on a generalization of Taylor's hypothesis concerning the evolution of magnetic helicity in plasma with a large magnetic Reynolds number.