[P-EM10] Dynamics of Magnetosphere and Ionosphere

[PEM10-12] A Space Hurricane over the Earth’s Polar Ionosphere

★Invited Papers

*Qing-He Zhang¹、Yong-Liang Zhang²、Chi Wang³、Kjellmar Oksavik^4,9、Larry R. Lyons⁵、Michael Lockwood⁶、Hui-Gen Yang⁷、Bin-Bin Tang³、Jøran Idar Moen^8,9、Zan-Yang Xing¹、Yu-Zhang Ma¹、Xiang-Yu Wang¹、Ya-Fei Ning¹⁰、Li-Dong Xia¹ (1.Institute of Space Sciences, Shandong University, Weihai, China、2.The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA、3.Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing, China、4.Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway、5.Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA、6.Department of Meteorology, University of Reading, Reading, UK、7.Polar Research Institute of China, Shanghai, China、8.Department of Physics, University of Oslo, Blindern, Oslo, Norway、9.The University Centre in Svalbard, Longyearbyen, Norway、10.School of Microelectronic, Shandong University, Jinan, Shandong, China)

キーワード：Aurora, Magnetosphere-ionosphere coupling, Space hurricane

In Earth’s low atmosphere, hurricanes are destructive due to their great size, strong spiral winds with shears, and intense rain/precipitation. However, disturbances resembling hurricanes have not been detected in Earth’s upper atmosphere. Here we report a long-lasting space hurricane in the polar ionosphere and magnetosphere during low solar and otherwise low geomagnetic activity. This hurricane shows strong circular horizontal plasma flow with shears, a nearly zero-flow center, and a coincident cyclone-shaped aurora caused by strong electron precipitation associated with intense upward magnetic field-aligned currents. Near the center, precipitating electrons were substantially accelerated to ~10 keV. The hurricane imparted large energy and momentum deposition into the ionosphere despite otherwise extremely quiet conditions. The observations and simulations reveal that the space hurricane is generated by steady high-latitude lobe magnetic reconnection and current continuity during a several hour period of northward interplanetary magnetic field and very low solar wind density and speed.