Dynamo Theories of Solar Flares

In flare models based on magnetic field reconnection, the energy is liberated in a very thin layer. This makes difficult an explanation of the high rate of energy release observed in solar flares. The limitation of these models is briefly discussed. Flare models based on the disruption of current flowing from the photosphere to the corona have been proposed. Direct currents can be generated by organized motions of the neutral photospheric plasma across the magnetic field. Observations of organized photospheric velocities are reviewed, and the main characteristics of the electric current system are presented.