Asymmetry in the Penetration Electric Fields in Both Hemispheres as a Function of Local Time and Conductivity During the March 2015 Storm
Abstract
During the initial phase of a large geomagnetic storm, the ionospheric polar cap electric field expands in extent and the field penetrates equatorward in both hemispheres. This penetration electric field presents itself as an enhancement of the zonal ion flows in the ionosphere. In earlier work we used the observed excess zonal ion flows from the various DMSP spacecraft in different local times during the March 2013 storm to determine the extent of the penetration electric field and compare them between both hemispheres as a function of local time. We found the penetration extents were essentially the same in both hemispheres on the nightside, but the penetration extents showed large differences between the hemispheres over in the dusk and afternoon regions. The cause of this penetration difference is not certain, but we suspect that the differences in the ionospheric conductivity between the dayside and nightside northern and southern hemispheres plays a primary role. For this presentation we have repeated this analysis on the March 2015 storm, again finding the same results: a near match in the penetration extents on the nightside and an asymmetric difference in the extents on the dayside. We will model the ionospheric conductivity at the locations of the DMSP observations during the March 2015 storm to estimate the differences in the conductivities between the northern and southern ionospheres. We will present the results of these model runs to see if there is indeed a correlation between the ionospheric conductivities and the penetration electric field extents during this storm.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMSA22C1892H