Effects of the Mother's Day superstorm event of 11 May 2024

2023-2024
The strongest geomagnetic storm for the last 20 years appeared during the night of 10 to 11 May 2024, caused by a big solar eruption that generated nice auroras visible in many European countries at unusual lower latitudes. It has been called the Mother’s Day event due to its date.

This geomagnetic storm had important consequences on the radiation belts, with the first observation of four electron belts and the exceptional injection of protons in the South Atlantic Anomaly, a region with a weak magnetic field.

Unprecedented observations of 4 electron belts

For the first time ever, four electron belts were observed in the magnetosphere until one month after the storm, contrasting with the usual two (inner and outer) radiation belts (Pierrard et al. 2024). We showed that this was due to an important loss of electrons at very specific positions. 

The observation was made by the Energetic Particle Telescope (EPT) and confirmed by the MetOp satellite. EPT is a detector that we developed together with Université Catholique de Louvain and Redwire Space. It was launched in 2013 on board the PROBA-V satellite at 820 km of altitude.

Exceptional injection of protons in the South Atlantic Anomaly

For the first time since the launch in 2013 of the PROBA-V satellite with the EPT, an injection of energetic protons in the South part of the South Atlantic Anomaly (SAA) was observed. 

These injected protons are well visible by the red region in Figure 3 illustrating the proton fluxes at 820 km altitude observed in the first EPT proton channel, averaged in longitude and latitude bins from 13 to 19 May 2024 after the storm. 

The variations of the EPT proton fluxes in the SAA during the previous maximum solar activity in 2014 and at minimum activity in 2019 showed already very different behaviours in the North and South part of this region, compared to quiet solar conditions (Pierrard et al., 2023).

References:

  • Pierrard V., Winant A., Botek E., and Péters de Bonhome M. (2024), The Mother’s Day solar storm of 11 May 2024 and its effect on Earth’s radiation belts, Universe, 10, 10, 391, https://doi.org/10.3390/universe10100391
     
  • Pierrard V., S. Benck, E. Botek, S. Borisov, A. Winant (2023), Proton flux variations during Solar Energetic Particle Events, minimum and maximum solar activity and splitting of the proton belt in the South Atlantic Anomaly, Journal of Geophysical Research: Space Physics, 128, e2022JA031202, https://doi.org/10.1029/2022JA031202.

 

SDO observations of the Sun
SDO (Solar Dynamics Observatory) observations of the Sun in May 2024. The active region on the right was the largest for the last 10 years and the origin of the solar eruption generating the Mother’s Day geomagnetic storm of 10-11 May 2024. Credit: NASA.
Graph PROBA-V/EPT smoothed electron differential fluxes
Figure 2. PROBA-V/EPT smoothed electron differential fluxes from 500 to 600 keV from 5 May 2024 (in dark blue, two belts) to 27 June 2024 (in red, 4 belts/peaks), revealing the formation of four electron belts one month after the 11 May storm, due to the loss of the injected electrons at very specific radial distances. This had never been observed before.
Map of EPT proton fluxes from 13 to 19 May 2024
Figure 3. Map of EPT proton fluxes in the energy range 9.5-13 MeV at 820 km averaged in longitude and latitude bins from 13 to 19 May 2024.
Aurora seen on 11 May 2024 in Belgium at unusual low latitudes
Figure 4. Aurora seen on 11 May 2024 in Belgium, at unusual low latitudes, resulting from the Mother’s Day event. (Credit: Gaël Cessateur, BIRA-IASB).