In this paper we examine a total of 16 dipolarization events that were observed by THEMIS spacecraft in space close togeosynchronous orbit, r < ~ 7 RE. For the identified events, we examine the characteristics of the plasma flows and associatedbubbles as defined based on pV5/3, where p is the plasma pressure and V the volume of unit magnetic flux. First, we find thatthe flow speed in the near-geosynchronous region is very low, mostly within a few tens of km/s, except for a very few events forwhich the flow can rise up to ~200 km/s but only very near the dipolarization onset time. Second, the bubble parameter, pV5/3,decreases by a much smaller factor after the dipolarization onset than for the events in the farther out tail region. We suggestthat the magnetic dipolarization in the near-geosynchronous region generates or is associated with only very weak plasmabubbles. Such bubbles in the near-geosynchronous region would penetrate earthward only by a small distance before theystop at an equilibrium position or drift around the Earth.

• Lee, Ji-Hee(Department of Astronomy and Space Science Chungbuk National University)
• Lee, Dae-Young( Department of Astronomy and Space Science Chungbuk National University) | Lee, Dae-Young
• Park, Mi-Young( Department of Astronomy and Space Science Chungbuk National University) | Park, Mi-Young
• Lee, Eun-Hee( Yonsei University Observatory, Yonsei U) | Lee, Eun-Hee