AUTHOR=Gong Fan , Yu Yiqun , Cao Jinbin 

TITLE=Simulating the Responses of the Magnetosphere–Ionosphere System to the IMF By Reversal

JOURNAL=Frontiers in Physics

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2022.900192

DOI=10.3389/fphy.2022.900192

ISSN=2296-424X

ABSTRACT=<p>The interplanetary magnetic field (IMF) B<sub>y</sub> component can cause asymmetric features in the magnetosphere-ionosphere system and influence the electromagnetic energy input. In this study, we use the Space Weather Modeling Framework (SWMF) to study the transient dynamics after a sudden change in the IMF B<sub>y</sub> component exerts on the magnetosphere system. Simulation results reveal that under northward IMF conditions, an abrupt change of the IMF B<sub>y</sub> from duskward to dawnward induces a dawnward geomagnetic field firstly in the cusp region and then in both the near-Earth and magnetotail regions. The signal of the new y-component of the geomagnetic field in the near-Earth region extends tailward while that in the magnetotail moves Earthward, leading the middle-tail region to react last. We investigate in detail the transitional change of the y-component of the geomagnetic field and compare it to the scenario under southward IMF conditions, and find that the latter case reacts in a much simpler manner and the responses are faster globally.</p>