[PEM13-P16] An extreme erosion of the plasmasphere during the 7–10 September 2017 storm
Keywords:plasmasphere, innner magnetosphere, Magnetosphere-ionosphere coupling
The electron density profiles reveal that the plasmasphere was severely eroded during the recovery phase of the storm and the plasmapause was located at L~1.7 at 23 UT on 8 Sep 2017. This is the first report of such deep erosion of the plasmasphere (LPP<2) with the in-situ observation of the electron density. The degree of the severity is much more than what is expected from the SYM-H minimum (–146 nT) of the event.
We further study absolute GNSS-TEC, ground-based magnetic field, the doppler velocity obtained from the SuperDARN Hokkaido Radars to investigate the location of the midlatitude ionospheric trough, the penetration of the convection electric field to the equator and middle latitudes, respectively. Our results suggest that the middle latitude electric field was penetrated from the high-latitude storm time convection for several hours. Futhermore, the Ionosphere-Plasmasphere-Electrodynamics (IPE) model (Sun et al., 2015; Maruyama et al., 2016) is used to understand the dynamics of the plasmasphere. The IPE results suggest that the middle latitude electric field penetrates from the high-latitude storm time convection that lasts for several hours can explain the degree of severity during the September 7-11 2017 storm.