The Ionospheric Responses from Satellite Observations within Middle Latitudes to the Strong Magnetic Storm on 25–26 August 2018

Abstract

The multi observations from the China Seismo-Electromagnetic Satellite (CSES) were presented and analyzed during the biggest magnetic storm on 25–26 August in the quiet solar activity year of 2018, together with the Swarm satellite and GNSS TEC (Global Navigation Satellite System, Total Electron Content). The whole tempo-spatial evolutional process was demonstrated in electromagnetic fields and in-situ plasma parameters within the whole magnetic storm time period of three phases, the main phase with quick decrease in SYM-H, the quick recovery phase, and the slow recovery phase. Strong correlations were revealed in time and space between electric fields and electron density. During the main phase, the penetrated electric field was the major factor to induce the injection of electric fields to low latitudes even to the equator and contribute to constructing the double peaks of Ne at altitudes above 500 km of CSES in daytime. In the quick recovery phase, Ne depletion was found in low middle and low latitudes in the daytime, associated with a quick decrease in solar wind dynamic pressure, but in the nightside Ne maintained or increased. Due to the high solar wind speed following the quick recovery phase, it controlled the enhancements in an electric field below 1125 Hz at medium and low latitudes in daytime and produced similar structures in a 225 Hz electric field with the mid-latitude trough of Ne in local nighttime and maintained their equator-ward movements in this time period. Ne/TEC showed typical local time-dependence in this magnetic storm, which illustrated that although the electron density in the ionosphere was mainly caused by this solar activity event, local background environments must also not be ignored for their final evolutional modes.

Ionosphere over Eastern North Atlantic Midlatitudinal Zone during Geomagnetic Storms

“…As reported in [48], from 25 August 2018 to 26 August 2018, intense ionospheric irregularities occurred in the equatorial region, observed at both sides of the equator, and extended considerably to higher latitudes (40°-45°). Considering the study by [49], the TEC increase for middle latitudes was more significant in the southern hemisphere (Africa) than in Europe.…”

“…Despite the intensity of ionospheric disturbances and the significant increase in electron density recorded, especially in the storm's main phase, no loss of lock or other As reported in [48], from 25 August 2018 to 26 August 2018, intense ionospheric irregularities occurred in the equatorial region, observed at both sides of the equator, and extended considerably to higher latitudes (40 • -45 • ). Considering the study by [49], the TEC increase for middle latitudes was more significant in the southern hemisphere (Africa) than in Europe.…”