Ionospheric Pc1 waves during storm recovery period observed by CSES and SWARM
Abstract
During storm recovery phase on 27th August 2018, typical Pc1 waves were seen by the Sodankylä and Kiruna stations on the ground for several hours simultaneously. Meanwhile, China Seismo-Electromagnetic Satellite (CSES) and SWARM find Pc1 wave activities both in the Northern and Southern hemispheres in the ionospheric F region, occurring in the high latitude post-midnight regions with a central frequency about 2Hz. In this paper, we study the propagation characteristics and possible source regions of those waves. Firstly, we find the satellites observed Pc1 waves have mixed polarizations and the wave normal directions are almost parallel to the background magnetic field, which imply the satellites are close to the wave injection region in the ionosphere at about L=3. Furthermore, we also find that the position of the plasmapause calculated by CCMC model and equation of Carpenter and Anderson is almost at L=3. Therefore, we suggest the possible sources of waves are near the plasmapause, which is consistent with previous studies that the outward expansion of the plasmasphere into the ring current during the recovery phase of geomagnetic storms may generate electromagnetic ion cyclotron (EMIC) waves and then these EMIC waves propagate along the background magnetic field northward and southward to the ionosphere at about L=3. Additionally, analysis of the ground station data shows that the amplitude of Pc1 waves decreases as the L-shell increases, with a maximum at about L=3, which supports the idea that CSES observes the wave activities near the injection region. The Pc1 wave power changes over time during the magnetic storm, which is observed by CSES, SWARM satellites, and confirmed by the ground station data.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E.681G