Three-Dimensional Simulation Study of the Magnetohydrodynamic Relaxation Process in the Solar Corona. II.

"Three dimensional dynamics of solar coronal magnetic loops, which is caused by the photospheric twisting motion, is investigated in detail by using magnetohydrodynamic numerical simulations. It is found that as a result of the rising of the magnetic loops, isolated flux tubes (plasmoids) are generated on the top of the loops through magnetic reconnection. During the reconnection process, the magnetic energy of the mode coupled with the potential field is partially converted into the mode decoupled from it. We also analyze the linear stability of the coupled mode and reveal that it is destabilized when the loop height and the magnetic helicity exceed the critical values predicted from the bifurcation theory (Kusano et al. 1995). Furthermore, we reveal that three dimensional mode couplings have an effect to concentrate the helicity into an unstable mode, as well as an effect to reduce the growth rate of the instability.