Three-dimensional self-organization of a magnetohydrodynamic plasma

A three-dimensinal self-organization process in an incompressible dissipative plasma is investigated by means of a magnetohydrodynamic simulation. Two typical phases are observed; i.e., an energy-relaxation phase and an inverse-cascade phase. In the relaxation phase the total magnetic energy rapidly decreases while the magnetic structure is transformed into a simpler one by magnetic reconnection. In the inverse-cascade phase the magnetic helicity spectrum shifts towards the low-wave-number region while the magnetic energy spectrum shifts towards the high-wave-number region.