Hemispheric and seasonal variations in the cold plasma outflow source region: Swarm and CHAMP observations of F -region polar cap electron density
Abstract
One of the primary mechanisms of loss of Earth's atmosphere is the persistent cold (temperatures less than ~20 eV) ion outflow that has been observed in the magnetotail and magnetospheric lobes over large volumes with dimensions of order several Earth radii. As the main source of this cold ion outflow,the relatively tiny polar cap F-region ionosphere and conditions within it have disproportionate influence on these magnetospheric regions. In this study we use 15 years of measurements by the Swarm spacecraft constellation and the CHAMP spacecraft of electron density N\small e made within the F region of the polar caps to investigate the morphology of this cold ion source. Altitude variation in Swarm and CHAMP N\small e measurements is accounted for through the derivation of an empirical scale height. The approximately linear dependence of polar cap N\small e on F10.7 is also included in the analysis to accurately uncover other dependencies. Preliminary analysis suggests interesting interhemispheric asymmetries, especially around the equinoxes, which could possibly have significant implications on magnetosphere plasma populations and dynamics.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E.685H