Two successive solar energetic electron events on 24 December 2022

We investigated two successive solar energetic electron (SEE) events observed by Solar Orbiter, associated with the same active region and separated by ∼25 minutes, on December 24, 2022. We performed the forward fitting to in situ temporal profiles to derive the solar injection profiles of SEEs, and utilized the extended pan-spectrum (EPS) fitting method to self-consistently determine the shape of SEE energy spectra. Then we examined the temporal relationship between SEE solar injections and candidate solar flares and/or coronal jets. After considering the effects of interplanetary propagation and instrumental response, we found that the SEE #1 (#2) event can be formed by three (two) solar injections that dominate, respectively, at łesssim22 keV, 22-290 keV, and 290-746 keV (at łesssim26 keV and 26-185 keV). In both events, the low-energy SEE injection starts earlier, peaks earlier and lasts longer as the electron energy decreases, producing a very hard power-law energy spectrum. The high-energy injection is roughly independent of energy in its timing, with a short duration of ∼3-6 minutes and a soft energy spectrum, which coincides with a B-C class flare, HXR burst, and coronal jet. The #1 event shows another, middle-energy injection with the start-time (duration) getting earlier (longer) but the peak-time growing earlier and then later as the electron energy decreases, and with a hard energy spectrum. In both SEE events, the low-energy injection likely comes from a progressive acceleration process occurring high in the corona, while the high-energy injection can arise from an instantaneous acceleration of the lower-energy electrons, accompanied by an HXR burst and/or coronal jet. In the #1 event, the middle-energy injection can result from an additional process, leading to a much more efficient acceleration at ≳25 keV. Thus, successive SEE events may form through very dynamic and complex processes.