Introducing a new ground-based Radiation belt electron enhancement events catalog

Electron radiation belt enhancement events are a key phenomena of the Earth geomagnetic activity and have been thoroughly studied in the literature.

Establishing extensive catalogs of these events automatically is a key asset to both the global statistical study of the electron radiation belt enhancement and, from an operational perspective, to provide actionable scenario-based forecasts. The latter being the objective of the EU Horizon Europe FARBES (Forecast of Actionable Radiation Belts Scenarios) under which this work is funded.

Nowadays, the existing attempts of establishments of such catalogs are scarce and often based on the exceedance of certain thresholds of ground-based measurements (Bernoux and Maget, 2020) or onboard electron fluxes (Reeves et al. 2020). Which often leads to missed events, non-events or events with unrealistic boundaries.

In this work, we introduce a novel automatic detection method of radiation belt enhancement events based on the Ca index (Rochel et al. 2016), a simple 1D-proxy representative of the state of the electron radiation belts for average energies (up to  MeV). This method is then used to produce an extensive catalog of events between 1870 and 2023 with more realistic boundaries. The most recent events of this catalog (detected after 1995) are then associated with their possible physical cause, whether it be Interplanetary Coronal Mass Ejections (ICMEs) or Streaming-Interaction regions (SIRs).