[P-EM09] Dynamics in magnetosphere and ionosphere

★ [PEM09-14] Direct observations of the full Dungey convection cycle in the polar ionosphere for southward IMF

*Qing-he ZHANG¹, Michael LOCKWOOD², John C. FOSTER³, Shun-rong ZHANG³, Bei-chen ZHANG⁴, Ian W. MCCREA⁵, Joran MOEN⁶, Mark LESTER⁷, J. michael RUOHONIEMI⁸ (1.Institute of Space Sciences, Shandong University,Weihai, Shandong, 264209, China, 2.Department of Meteorology, University of Reading, Earley Gate, Post Office Box 243, RG6 6BB, UK, 3.MIT Haystack Observatory, Westford, MA 01886, USA, 4.Polar Research Institute of China, Shanghai, China, 5.Space Sciences Division, SSTD, Rutherford Appleton Laboratory, Didcot, UK, 6.Department of Physics, University of Oslo, Blindern, Oslo, Norway, 7.Department of Physics and Astronomy, University of Leicester, Leicester, UK, 8.Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA)

Keywords:Dungey convection cycle, Magnetic reconnection, polar cap patches

Tracking the formation and full evolution of polar cap ionization patches in the whole polar ionosphere, we directly observe the full Dungey convection cycle for southward interplanetary magnetic field (IMF) conditions. The patches were segmented from the tongue of ionization (TOI) at the equatorward edge of the cusp by the expansion and contraction of the polar cap boundary (PCB) due to the pulsed dayside magnetopause reconnection indicated by in-situ THEMIS observations. Convection leads to the patches entering the polar cap and being transported antisunward across the polar cap along the streamlines continuously monitored by the globally distributed arrays of GPS receivers and SuperDARN radars. The pulsed nightside reconnections, occurring as part of the magnetospheric substorm cycle, modulated the exit of the patches from the polar cap, as confirmed by the coordinated observations of the magnetometer at Tromso and EISCAT Tromso UHF Radar. After exiting the polar cap, the patches broke up into a number of plasma blobs, and returned sunward in the auroral flow of the dawn and/or dusk convection cell. The full evolution time, corresponding to the full circulation of energy and momentum from the solar wind to the magnetosphere, is about three hours.