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1. MAGE Model Simulation of the Pre‐Reversal Enhancement and Comparison With ICON and Jicamarca ISR Observations

   https://doi.org/10.1029/2023JA032038  

   Wu, Qian; Wang, Wenbin; Lin, Dong; Qian, Liying; Huang, Chaosong; Zhang, Yongliang (June 2024, Journal of Geophysical Research: Space Physics)

   Abstract Using the latest coupled geospace model Multiscale Atmosphere‐Geospace Environment (MAGE) and observations from Jicamarca Incoherent scatter radar (ISR) and ICON ion velocity meter (IVM) instrument, we examine the pre‐reversal enhancement (PRE) during geomagnetic quiet time period. The MAGE shows comparable PRE to both the Jicamarca ISR and ICON observations. There appears to be a discrepancy between the Jicamarca ISR and ICON IVM with the later showed PRE about two times larger (∼40 m/s). This is the first time that MAGE is used to simulate the PRE. The results show that the MAGE can simulate the PRE well and are mostly consistent with observations. 

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2. Penetrating electric field during the Nov 3–4, 2021 geomagnetic storm

   https://doi.org/10.1016/j.jastp.2024.106219  

   Wu, Qian; Wang, Wenbin; Lin, Dong; Huang, Chaosong; Zhang, Yongliang (April 2024, Journal of Atmospheric and Solar-Terrestrial Physics)

   We simulated the Nov 3-4, 2021 geomagnetic storm event penetrating electric field using the Multiscale Atmosphere-Geospace Environment (MAGE) model and compared with the NASA ICON observation. The ICON observation showed sudden enhancement of the vertical ion drift when the penetrating electric field arrived at the equatorial region. The MAGE model simulated vertical ion drifts have the similarly fast enhancement that shown in the ICON data at the same UT time and satellite location. Hence, ICON ion drift data was able to verify MAGE simulation, which couples the magnetospheric model was able to simulate the penetrating electric field very well. 

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3. New Expression of the Field‐Line Integrated Rayleigh‐Taylor Instability Growth Rate

   https://doi.org/10.1029/2024JA032550  

   Huang, Chun‐Yen; Fang, Tzu‐Wei; Richmond, Arthur D; Fuller‐Rowell, Timothy J; Liu, Jann‐Yenq (August 2024, Journal of Geophysical Research: Space Physics)

   An expression of Rayleigh‐Taylor (R‐T) instability growth rate based on the field‐line integrated theory is newly established. This expression can be directly utilized in ionosphere models with magnetic flux tube structure based on Modified Apex Coordinates. The R‐T instability growth rates are calculated using the thermospheric and ionospheric conditions based on the coupled Whole Atmosphere Model and Ionosphere Plasmasphere Electrodynamic model (WAM‐IPE). The parameters used in this calculation include the field‐line integrated conductivities and currents, which consider the Quasi‐Dipole Coordinates and the modifications to the equations of electrodynamics. Detailed description of the new formulas and comprehensive analyses of diurnal, longitudinal, and seasonal variations of the R‐T instability growth rate are carried out. The dependencies of growth rates on pre‐reversal enhancement (PRE) vertical drifts and solar activity are also examined. The results show that pronounced R‐T growth rates are captured between 18 and 22 local time (LT) when strong PRE occurs in the equatorial ionosphere. The simulated R‐T growth rate increases with increasing solar activity levels and demonstrates strong correlations with the angle between the sunset terminator and the geomagnetic field line. These results are consistent with plasma irregularity occurrence rates shown in various satellite observations, suggesting that the newly developed R‐T growth rate calculation can effectively capture the probability of irregularities by considering the changes along magnetic flux‐tubes in the ionosphere. Since the WAM‐IPE is running in operation at National Oceanic and Atmospheric Administration Space Weather Prediction Center, the new calculations can be potentially implemented in the near future to provide forecasted information of the R‐T growth rate. 

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4. Ionosphere‐Thermosphere Responses to the March 2023 Geomagnetic Storm Using Observations and TIEGCM Simulations Driven by Data Assimilated Aurora and Electric Fields

   https://doi.org/10.1029/2025JA034954  

   Poudel, Prakash; Lu, Xian (June 2026, Journal of Geophysical Research: Space Physics)

   Abstract We investigate Ionosphere‐Thermosphere (IT) responses to the March 2023 geomagnetic storm using GOLD and PFISR observations, along with TIEGCM simulations driven by data‐assimilated aurora and electric fields. A Lattice Kriging approach is implemented to assimilate auroral electron flux and characteristic energy from ground‐based (THEMIS/ASIs) and satellite (DMSP/SSUSIs) measurements, and the empirical model (Zhang & Paxton, 2008,https://doi.org/10.1016/j.jastp.2008.03.008). Electric field assimilation uses SuperDARN ion drifts, PFISR, and the SuperDARN SHF potential model. Compared to the default run, the assimilated simulation better captures GOLD observations, including an O/N₂depletion by ∼0.5, and a neutral temperature enhancement of ∼170 K relative to a quiet day. These changes are primarily driven by enhanced Joule heating from assimilated aurora and electric fields, and the resultant upwelling. Results from different model runs implies that aurora modestly increases temperature, while electric fields further enhance it and modulate its spatial structure. The assimilated run also captures the local PFISR observations, including (a) F‐region elevated ion and electron temperatures (∼4000 K); (b) a negative ionospheric storm phase with ∼60% F‐region electron density reduction; and (c) E‐region electron density enhancements by 50%, relative to a quiet day. Electric fields more strongly elevate ion temperature and reduce F‐ region electron density, whereas aurora drives E‐region electron density enhancements. The combined effect of both drivers produces the largest height‐integrated Joule heating at the Poker Flat, reaching ∼120 mW/m². Overall, we demonstrate that assimilating high‐latitude drivers into TIEGCM significantly improves its capability to simulate storm‐time IT dynamics with richer spatial structures and increased variability. 

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5. Penetrating Electric Field With/Without Disturbed Electric Fields During the 7–8 July 2022 Geomagnetic Storm Simulated by MAGE and Observed by ICON MIGHTI

   https://doi.org/10.1029/2024JA033240  

   Wu, Qian; Lin, Dong; Wang, Wenbin; Pham, Kevin; Qian, Liying; Wu, Haonan; Immel, Thomas J; Yiğit, Erdal (April 2025, Journal of Geophysical Research: Space Physics)

   Abstract Penetrating and disturbed electric fields develop during geomagnetic storms and are effective in driving remarkable changes in the nightside low latitude ionosphere over varying time periods. While the former arrive nearly instantaneously with the changes in the solar wind electric field, the latter take more time, requiring auroral heating to modify upper atmospheric winds globally, leading to changes in the thermospheric wind dynamo away from the auroral zones. Such changes always differ from the quiet time state where the winds are usually patterned after daytime solar heating. We use the Multiscale Atmosphere‐Geospace Environment model (MAGE) and observations from the NASA Ionospheric Connection Explorer (ICON) mission to investigate both during the 7–8 July 2022 geomagnetic storm event. The model was able to simulate the penetrating and disturbed electric fields. The simulations showed enhanced westward winds and the wind dynamo induced upward ion drift confirmed by the ICON zonal wind and ion drift observations. The simulated zonal wind variations are slightly later in arrival at the low latitudes. We also see the penetrating electric field opposes or cancels the disturbed electric field in the MAGE simulation. 

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