DISSIPATION OF MAGNETIC ENERGY IN THE SOLAR CORONA

Magnetic field lines that are embedded in a moving, highly conducting plasma naturally evolve so that the magnetic energy dissipation nj2 increases exponentially in time until the dissipation approaches the rate of magnetic energy input. The basic requirement on the plasma flow is that it be chaotic, which means neighboring points in the flow separate exponentially with time. The flows in the solar photosphere, which are driven by solar convection, may not only pump the required energy into a large-scale magnetic field to heat the corona but also amplify the currents sufficiently to rapidly thermalize that energy through nj2 heating.