Symmetry breaking and nonlinear wave-wave interaction in current disruption: Possible evidence for a phase transition

Magnetospheric substorms are generally accompanied by sporadic and intermittent large magnetic fluctuations in the magnetotail. These fluctuations are related to the disruption of the cross-tail current. Here, we have applied different techniques to a case study of this phenomenon. In detail, we have investigated the change on the scaling properties of the magnetic field fluctuations and the occurrence of short-lived nonlinear coupling in the magnetic field fluctuations as current disruption progresses. Clear evidence is found for a change of the scaling properties during the current disruption and the existence. of short-lived phase-coupling structures, supporting the hypothesis of the occurrence of a reorganization process. These characteristics about current disruption are discussed in the framework of self-organized criticality and phase transitions out of equilibrium.