Frontiers in Astronomy and Space Sciences—Yu Hong, Yue Deng, Qingyu Zhu, Astrid Maute, Marc Hairston, Cheng Sheng, Daniel Welling, and Ramon Lopez
The inter-hemispheric asymmetry (IHA) in the Earth’s ionosphere-thermosphere (IT) system can be pronounced during geomagnetic storms and its cause remains unclear. The IHA in the high-latitude electrodynamic forcings (e.g., ion convection and auroral particle precipitation) can contribute to the observed IHA in the IT system but a comprehensive understanding of the pathway is lacking. Numerical simulations could help address this question but accurate specifications of high-latitude forcings are needed. In this study, we utilize field-aligned currents (FACs) obtained from the Active Magnetosphere and Planetary Electrodynamics Response Experiment data set to specify the high-latitude electric potential in the Global Ionosphere and Thermosphere Model (GITM) to examine the IHAs in the IT system during the 8-9 October 2012 storm. It is found that the FAC-driven GITM simulation overperforms the simulation driven by empirical models in terms of capturing the spatiotemporal variations of the high-latitude ion convection. Meanwhile, it is found that the cross-polar-cap potential, hemispheric power and the convection equatorial boundary display significant IHAs. Furthermore, the thermospheric response during this storm are studied. It is found that the FAC-driven GITM simulation can well capture the neutral density response observed by the Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite on the dusk-side. In addition, the IHA in the neutral density response follows the IHA in the Joule heating dissipation with a time delay of ~3 h. Our study helps to improve the understanding of storm-time IHA in the high-latitude forcings and its effects on the IT system.