Solar coronal magnetic field structure and observed energy release locations

MANDRINI, C.H.

Córdoba

Workshop; V Friends of Friends; 2015

IATE

The magnetic field is thought to be the source of the energy released in diverse observed coronal phenomena, from the less energetic coronal heating to the most violent flares and prominence eruptions. These phenomena involve not only very different scales from the energetic, but also from the temporal, point of view. Magnetic field reconnection, which is efficient only at very small spatial scales, has been the energy release mechanism so far proposed. From a theoretical point of view, magnetic configurations with a complex structure or topology, i.e. having separatrices, are the ones where current sheets can form in 2D. When going to 3D a complete description is given by the skeleton formed by null points, spines, fans and separators, and associated separatrices. The analysis of the structure of numerous active regions has shown that active phenomena occur in a larger variety of configurations than the previous ones. Quasi-separatrix layers (QSLs), which are regions where there is a drastic change in field-line linkage, generalize the concept of separatrices. Numerical results show that magnetic reconnection at QSLs occurs when the self-pinching of the current layers is strong enough to efficiently enhance the dissipation term in the induction equation. A property of this reconnection process is the continuous slippage of field lines along each other as they pass through the current layers. We review observed regions showing varied levels of activity and their topologies, and discuss numerical results, which show that magnetic reconnection can occur in configurations having a wide range of topological characteristics.