Assessment of Using Field‐Aligned Currents to Drive the Global Ionosphere Thermosphere Model: A Case Study for the 2013 St Patrick’s Day Geomagnetic Storm

Abstract

In this study, field‐aligned currents (FACs) obtained from the Active Magnetosphere and Planetary Electrodynamics Response Experiment data set have been used to specify the high‐latitude electric potential in the Global Ionosphere Thermosphere Model (GITM). The advantages and challenges of the FAC‐driven simulation are investigated based on a series of numerical experiments and data‐model comparisons for the 2013 St Patrick's Day geomagnetic storm. It is found that the cross‐track ion drift measured by the Defense Meteorological Satellite Program satellites can be well reproduced in the FAC‐driven simulation when the electron precipitation pattern obtained from Assimilative Mapping of Ionospheric Electrodynamics (AMIE) technique is used in GITM. It is also found that including the neutral wind dynamo properly is very important when using FACs to derive the high‐latitude electric field. Without the neutral wind dynamo, the cross‐polar‐cap potential and hemispheric integrated Joule heating could be underestimated by more than 20%. Moreover, the FAC‐driven simulation is able to well reproduce the ionospheric response to the geomagnetic storm in the American sector. However, the FAC‐driven simulation yields relatively larger data‐model discrepancies compared to the AMIE‐driven GITM simulation. This may result from inaccurate Joule heating estimations in the FAC‐driven simulation caused by the inconsistency between the FAC and electron precipitation patterns. This study indicates that the FAC‐driven technique could be a useful tool for studying the coupled ionosphere and thermosphere system provided that the FACs and electron precipitation patterns can be accurately specified.

Inter-hemispheric asymmetries in high-latitude electrodynamic forcing and the thermosphere during the October 8–9, 2012, geomagnetic storm: An integrated data–Model investigation

“…This subsection gives a brief overview of the FAC-driven procedure used in this study, and details can be found in Maute et al (2021) and Zhu et al (2022). The first step is to calculate the high-latitude electric potential (Φ R ) based on the current continuity equation:…”

“…In addition, the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) technique (Richmond and Kamide, 1988) can provide high-latitude electric potential and electron precipitation patterns used for driving GCMs (Lu et al, 2014;Lu et al, 2020). The Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) gives another alternative way to calculate the high-latitude electric potential by using the derived FAC and pre-defined electron precipitation or ionospheric conductance patterns (Maute et al, 202l;Robinson et al, 2021;Zhu et al, 2022), which shows improved agreement between simulations and experimental data in driving GCMs for storms (Maute et al, 202l;Maute et al, 2022;Zhu et al, 2022b).…”

Relative Contributions of Field‐Aligned Currents and Particle Precipitation to Inter‐Hemispheric Asymmetry at High Latitudes During the 2015 St. Patrick's Day Storm

“…Therefore, it is helpful to engage numerical experiments to assist in separating the asymmetric responses to FACs and PP. As demonstrated by several previous studies (Hong et al, 2023;Maute et al, 2021;Zhu, Lu, Maute, et al, 2022), the FAC-driven procedure with pre-defined electron precipitation patterns can improve the accuracy of high-latitude forcing and reproduce the storm-time global I-T system response as compared to simulations driven by empirical models. Utilizing a similar approach, the 2015 St. Patrick's Day storm has been chosen as a test case for simulation since it is a well-studied storm with extensive observations.…”

Investigation of Interhemispheric Asymmetry of the Thermospheric Composition Observed by GOLD During the First Strong Geomagnetic Storm in Solar‐Cycle 25, 1: IMF By Effects

“…With higher solar EUV radiation, the summer hemisphere will have a larger neutral temperature and neutral mass density (Sutton et al., 2009; Yu et al., 2020), which causes stronger pressure gradient force to influence the neutral winds (Dhadly & Conde, 2017; Dhadly et al., 2017), as well as the large‐scale summer‐to‐winter thermospheric circulation (Qian et al., 2016). Additionally, the different solar EUV radiation also generates different ionospheric conductance (Ridley, 2007) and field‐aligned currents (Workayehu et al., 2020), which impacts the Joule heating at high latitudes (Knipp et al., 2021; Zhu, Lu, & Deng, 2022; Zhu, Lu, Maute, et al., 2022). As indicated by Qian et al.…”