南向行星际磁场条件下在极区电离层对整个Dungey循环的直接观测

摘要

Tracking the formation and full evolution of polar cap ionization patches in the polar ionosphere,we directly observe the full Dungey convection cycle for southward interplanetary magnetic field (IMF) conditions.This enables us to study how the Dungey cycle influences the patches' evolution.The patches were initially segmented from the dayside storm enhanced density plume at the equatorward edge of the cusp,by the expansion and contraction of the polar cap boundary due to pulsed dayside magnetopause reconnection,as indicated by in situ Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations.Convection led to the patches entering the polar cap and being transported antisunward,while being continuously monitored by the globally distributed arrays of GPS receivers and Super Dual Auroral Radar Network radars.