CORONAL HEATING AND SOLAR-ACTIVITY - THE ROLE OF WAVES

Coronal heating and solar activity are manifestations of the complex interaction between the magnetic field and the photospheric plasma motions. As a result of such an interaction magnetohydrodynamic waves are generated: their dissipation may provide the basic physical mechanism to heat the corona. This paper describes the present status of knowledge of the physics underlying the dissipation of MHD waves. After having stressed the importance of the formation of small spatial scales for achieving an efficient dissipation, we review the theory of linear MHD waves in nonuniform media based on a normal mode approach. We then present the results of some recent numerical experiments and interpret them in the framework of the theory of MHD turbulence. A plan of future work will also be presented.