Polar Cap Boundary Reaction to Geomagnetic Storms
- 1University of New Hampshire, Space Science Center, Durham, NH, United States of America (j.raeder@unh.edu)
- 2CIRES, University of Colorado, Boulder, CO, USA
- 3LASP, University of Colorado, Boulder, CO, USA
- 4EPSS, UCLA, Los Angeles, CA, USA
It is well known that the polar cap, delineated by the Open
Closed field line Bound ary (OCB), responds to changes in the
Interplanetary Magnetic Field (IMF). In general, the boundary
moves equatorward when the IMF turns southward and contracts
poleward when the IMF turns northward. However, observations of
the OCB are spotty and limited in local time, making more
detailed studies of its IMF dependence difficult. Here, we
simulate five solar storm periods with the coupled
OpenGGCM-RCM-CTIM model to estimate the location and dynamics of
the OCB. For these events, polar cap boundary location
observations are also obtained from Defense-Meteorological
Satellite Pro- gram (DMSP) precipitation spectrograms and
compared with the model output. There is a large scatter in the
DMSP observations and in the model output. However, we generally
find good agreement between the model and the observations. On
average, the model overestimates the latitude of the open-closed
field line boundary by 1.61◦. Additional analysis of the
simulated polar cap boundary dynamics across all local times
shows that the MLT of the largest polar cap expansion closely
correlates with the IMF clock angle; that the strongest
correlation occurs when the IMF is southward; that during strong
southward IMF the polar cap shifts sunward; and that the polar
cap rapidly contracts at all local times when the IMF turns
northward.
How to cite: Raeder, J., Tulegenov, B., Cramer, W. D., Ferdousi, B., Fuller-Rowell, T., Maruyama, N., and Strangeway, R. J.: Polar Cap Boundary Reaction to Geomagnetic Storms, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3173, https://doi.org/10.5194/egusphere-egu22-3173, 2022.
