Dynamical investigation of three-dimensional reconnection in quasi-separatrix layers in a boundary-driven magnetic field

Quasi-separatrix layers are regions in space where the mapping of field lin e connectivity changes especially rapidly. These layers have been suggested as special locations in three-dimensional magnetic fields that may host ma gnetic reconnection. Previous investigations have been analytical and have taken different simplifying: assumptions to investigate the problem. This p aper takes a numerical approach to investigate the dynamical properties of quasi-separatrix layers. The magnetic topology is stressed using: drivers s uggested by the analytical investigations but modified to fit the adopted b oundary conditions. The experiments show that current; does accumulate at s pecific locations in the numerical domain. The current magnitude and locati on depend strongly on the profile of the imposed driver, and they are found to be generated by the changes in field line parts imposed by the driving. They are therefore the manifestation of free magnetic energy in the pertur bed magnetic field. After the stressing of the field has stopped, it is fou nd that the plasma pressure is able to balance the Lorentz force of the str essed magnetic field and prevent a. continued growth of the current amplitu de in the current layers. Field-line changes are produced in the experiment s that include magnetic resistivity. The reconnection takes place at locati ons where the electric field component along the magnetic field is large. T he changes in field-line connectivity initiate flow velocities across the m agnetic field lines at only a small fraction of the local Alfven velocity.