Turbulent magnetic reconnection and Quasi-separatrix layers

MANDRINI, C.H.; MILANO, L.J.; DMITRUK, P.; GÓMEZ, D.O.; DÉMOULIN, P.

Tandil

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

Solar coronal loops are driven at their footpoints by the photosphericvelocity field. Although the typical timescale for this driving action is relatively slow (about 1000 seconds), it can give rise to reconnection phenomena occurring on the much shorter Alfv\'en time (10 to 100 seconds). To simulate such a process, we run a pseudo-spectral magnetohydrodynamic code. Boundary and initial conditions are chosen to ensure the development of a current layer and  force the field lines between two flux tubes to reconnect. During the process, we find a remarkable coincidence between the location of the current layer and the location of Quasi-Separatrix Layers, which are thin magnetic volumes where the field line connectivity changes abruptly. Another important result of this simulation is the observed transient of strong magnetohydrodynamic turbulence characterized by a $k^{-3/2}$ energy spectrum. This transient reaches its peak activity in coincidence with a maximum in the energy dissipation rate, thus suggesting that the direct energy cascade associated with this turbulent transient plays a key role in enhancing energy dissipation in magnetic reconnection processes.