3-DIMENSIONAL SIMULATION STUDY OF THE MAGNETOHYDRODYNAMIC RELAXATION PROCESS IN THE SOLAR CORONA .1. SPONTANEOUS GENERATION OF TAYLOR-HEYVAERTS-PRIEST STATE

The magnetohydrodynamic (MHD) relaxation process in the solar coronal magnetic field is investigated in detail by using a three-dimensional MHD numerical simulation. The interaction between the magnetic loops which are located periodically above the photosphere is mainly considered. It is found that when each foot of the loops is twisted by the photospheric motion the loops aligned along the magnetic inversion line are reconnected with each other. The magnetic reconnection process successively proceeds, and as a result a large-scale magnetic field parallel to the inversion line is spontaneously generated. The process is an MHD relaxation process where the magnetic configuration evolves toward a linear force-free field as predicted by Taylor and by Heyvaerts & Priest. The Taylor-Heyvaerts-Priest hypothesis about the selective dissipation of the energy compared to the magnetic helicity is numerically verified. It is observed that a magnetic dip, which is a favorable environment for the prominence condensation, is spontaneously generated through the relaxation process. Finally, the solar flare as a relaxation process of the magnetic energy is discussed, based on the simulation results.