Ballooning‐interchange instability in the near‐Earth plasma sheet and auroral beads: Global magnetospheric modeling at the limit of the MHD approximation

摘要: Explosive magnetotail activity has long been understood in the context of its auroral manifestations. While global models have used to interpret and understand many magnetospheric processes, temporal spatial scales some forms inaccessible modeling creating a gulf between observational theoretical studies these phenomena. We present here an important step toward bridging this using newly developed magnetosphere-ionosphere model with resolution capturing ≲ 30 km azimuthal zone. In magnetohydrodynamic (MHD) simulation growth phase synthetic substorm, we find self-consistent formation destabilization localized magnetic field minima near-Earth magnetotail. demonstrate that is due ballooning-interchange instability which drives earthward entropy bubbles embedded fronts. Finally, show create field-aligned current structures manifest ionosphere properties matching observed beads.