Premium
Small‐Scale Aurora Associated With Magnetospheric Flow Vortices After a Solar Wind Dynamic Pressure Decrease
Author(s) -
Zhao Huayu,
Zhou XuZhi,
Zong QiuGang,
Weygand James M.,
Shi Quanqi,
Liu Ying,
Yao Zhonghua,
Wang Yongfu,
Shen XiaoChen,
Ren Jie,
Liu Han,
Tian Anmin
Publication year - 2019
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2018ja026234
Subject(s) - vortex , solar wind , dynamic pressure , physics , meteorology , atmospheric sciences , environmental science , scale (ratio) , magnetopause , geophysics , mechanics , geology , astronomy , plasma , quantum mechanics
Sudden changes of the solar wind dynamic pressure have significant impacts on the dynamics of the magnetosphere‐ionosphere system. On 18 February 2011, a sudden decrease in solar wind dynamic pressure was observed by the Wind satellite, which drove the entire magnetosphere‐ionosphere system as recorded in many ground‐based and space‐based measurements. In the magnetosphere, Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft observed a counterclockwise plasma flow vortex propagating tailward. Near the magnetic footprints of the THEMIS spacecraft, the ground magnetometers observed magnetic field variations that corresponded to a counterclockwise vortex in the equivalent ionospheric currents, which in turn indicated the presence of upward field‐aligned currents. The all‐sky imager at RANK station near the THEMIS footprints also observed a simultaneous enhancement of the auroral brightness. Therefore, this comprehensive case study demonstrates a causal chain that links the solar wind dynamic pressure variations to magnetospheric, ionospheric, and auroral activities.