The solar cycle 25 multi-spacecraft solar energetic particle event catalog of the SERPENTINE project

We present a new multi-spacecraft SEP event catalog for events observed in solar cycle 25. Observations from five different viewpoints are utilized, which are provided by Solar Orbiter, Parker Solar Probe, STEREO A, BepiColombo, and the near-Earth spacecraft Wind and SOHO. The catalog is an output of the SERPENTINE project, funded through the European Union’s Horizon 2020 framework programme. We provide key SEP parameters for > 25 MeV protons, > 1 MeV electrons, and ∼100 keV electrons. Furthermore, basic parameters of the associated flare and type-II radio burst are listed, as well as the coordinates of the observer and solar source locations.

An event is included in the catalog if at least two spacecraft detect a significant proton event with energies > 25 MeV. SEP onset times are determined using the Poisson-CUSUM method. SEP peak times and intensities refer to the global intensity maximum. If different viewing directions are available, we use the one with the earliest onset for the onset determination and the one with the highest peak intensity for the peak identification. We furthermore aim at using the highest possible time resolution. Therefore, time averaging of the SEP intensity data is only applied if necessary to determine clean event onsets and peaks. 

Associated flares were identified using observations from near Earth and Solar Orbiter. Associated type II bursts were determined from ground-based observations in the metric frequency range and from spacecraft observations in the decametric range.

The current version of the catalog contains 45 multi-spacecraft events observed in the period from Nov 2020 until May 2023, of which 13 were widespread events and four were classified as narrow-spread events. Using X-ray observations by GOES/XRS and Solar Orbiter/STIX we were able to identify the associated flare in all but four events. Using ground-based and spacecraft radio observations we found an associated type-II radio burst for 40 events. In total the catalog contains 141 single event observations out of which 18 (39) have been observed at radial distances below 0.6 AU (0.8 AU). 

We acknowledge funding by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 101004159 (SERPENTINE).