Equatorial Ionospheric Electrodynamics Over Jicamarca During the 6-11 September 2017 Space Weather Event

摘要

We use the observations from the incoherent scatter radar and the magnetometers over Jicamarca (11.95° S, 76.87° W) sector to investigate the equatorial ionospheric electrodynamics on 6-11 September 2017. In this period, there are three X-class solar flares peaked at 12:02, 14:36, and 16:06 UT on 6, 7, and 10 September, respectively, in the local daytime of Jicamarca and a storm with the minimum SYM-H of -146 nT at 01:08 UT on 8 September. The results reveal that the three X-class flares drive the westward disturbance electric field in equatorial region. The flares intensify the westward and eastward equatorial electrojets on 6 and 10 September, while the eastward equatorial electrojet enhances first and then declines on the 7 September flare. The depletion in equatorial electrojet during flare is suggested to be the effects of the weakened electric field. In the storm recovery, the disturbance electric field is westward at ~10-16 LT and eastward at postmidnight and early morning sectors on 9-11 September, which is mainly driven by disturbance dynamo electric field (DDEF). Further, it is found that the westward DDEF first occurs at high altitudes and then at low altitudes around 10 LT, and the westward DDEF at 200-500 km has magnitudes increasing with altitudes. Meanwhile, the Jicamarca incoherent scatter radar observations show distinct altitudinal differences in the responses of the F region electron density to the disturbance electric field.