EGU25-19863, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-19863
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Extreme two-phase change of the ionospheric electron temperature overshoot during geomagnetic storms uncovered by neural networks
Artem Smirnov1,2, Yuri Shprits2,3, Hermann Lühr2, Alessio Pignalberi4, Elena Kronberg1, Fabricio Prol5,6, and Chao Xiong7
Artem Smirnov et al.
  • 1Ludwig Maximilian University of Munich, Earth and Environmental Sciences, Geophysics, Munich, Germany (arsmirnov95@gmail.com)
  • 2GFZ Helmholtz Research Centre Centre for Geosciences, Potsdam, Germany
  • 3Department of Earth, Planetary and Space Sciences, University of California Los Angeles (UCLA), CA, USA
  • 4Instituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy
  • 5Finnish Geospatial Research Institute (FGI), National Land Survey of Finland (NLS), Espoo, Finland
  • 6School of Technology and Innovation, University of Vaasa, Vaasa, Finland
  • 7Department of Space Physics, College of Electronic Information, Wuhan University, Wuhan, China

An intense surge in equatorial electron temperature (Te) at sunrise, known as the morning Te overshoot, has been one of the most widely studied ionospheric features since its discovery in the early Space Age. Despite extensive research, its behavior during geomagnetic storms remains poorly understood. Using global electron temperature observations by the CHAllenging Minisatellite Payload (CHAMP) mission in 2002-2010, we develop a neural network Te model, which helped us uncover a two-stage response of the morning Te overshoot to geomagnetic activity. During the storm’s main phase, electron temperatures in the overshoot region exhibit a pronounced enhancement, which is followed by a dramatic depletion exceeding 1000 K and the disappearance of the overshoot during the recovery phase. This two-phase evolution corresponds to the initial impact of a westward prompt penetration electric field (PPEF), which reduces electron densities therefore allowing for a more efficient energy exchange between the newly ionized particles at sunrise and lower energy (depleted) ambient plasma. The initial PPEF influence is overtaken by the eastward disturbance dynamo field later in the storm, which flips the ExB drift from downward to upward and lifts more electrons into the F-region. Increased electron densities enhance the cooling rates leading to the disappearance of the overshoot in the recovery phase of the storms. Our findings shed new light on the dynamics of the morning electron temperature overshoot and highlight the capability of digital twin models to uncover previously unrecognized physical phenomena in the near-Earth space environment. Additionally, we discuss the applications of the developed model for various ionospheric applications, including the calibration of electron temperatures from Swarm Langmuir Probes. 

How to cite: Smirnov, A., Shprits, Y., Lühr, H., Pignalberi, A., Kronberg, E., Prol, F., and Xiong, C.: Extreme two-phase change of the ionospheric electron temperature overshoot during geomagnetic storms uncovered by neural networks, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19863, https://doi.org/10.5194/egusphere-egu25-19863, 2025.