Magnetic topology and energy release in the solar corona

MANDRINI, C.H.

Tandil

Workshop; VIII Latin-American Workshop on Plasma Physics; 1998

Conferencia invitada  The magnetic field is thought to be the source of the energy released in the many and varied 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; that is to say, from the continuous supply of $10^{26} erg s^{-1}$ for coronal heating, to $10^{32} - 10^{33} erg$ in $10^2 s$ for the most powerful flares and prominence eruptions. Therefore, the mechanism reponsible for the release of energy needs to be versatile enough to account for such a wide scale range. Magnetic field reconnection has been the mechanism that has so far been proposed. Unfortunately, in theoretical reconnection models, the conversion of magnetic to thermal and kinetic plasma energy occurs on spatial scales that are far smaller than can be observed directly by present-day solar instrumentation.   We have developed a method of analysis that, based in the study of the topological characteristics of the magnetic field of solar active regions, has allowed us to find observational evidences in support of magnetic reconnection, and also to characterize the locations where magnetic reconnection would occur. We describe here the different steps through which our method has evolved and show examples of its application to observed flaring and non-flaring magnetic configurations, and also to theorical models of coronal loops, to attack both the coronal heating and prominence eruption problems.