Abstract
One of the prominent effects of space weather is the variation of
electric currents in the magnetosphere and ionosphere, which give rise
to rapid geomagnetic field variations on the surface of the Earth. These
Geomagnetic Disturbances (GMDs) can be highly localized and large
amplitude. Because the causes of localized GMDs are unresolved, we seek
to identify the physical drivers of these localized dB/dt spikes
measured by ground magnetometers. We use the Space Weather Modeling
Framework (SWMF) models to simulate the magnetosphere and reproduce
these small-scale spikes. We use the operational Geospace configuration,
which couples a global magnetohydrodynamic model to a height-integrated
ionospheric electrodynamics solver and a kinetic ring current model. We
run a series of simulations with increasingly higher spatial resolution
to resolve small scale dB/dt dynamics. We quantify the success of the
model against observation using Regional Station Difference (RSD), a
metric calculated using dB/dt or geoelectric field to pinpoint when a
single magnetometer station records a significantly different value than
others within a given radius. We discuss future work to improve the
model’s accuracy and our understanding of these small-scale structures.