Running summarizing tools on a new article

Abstract: Abstract Gradual solar energetic particle (GSEP) events, accelerated by coronal mass ejection (CME)–driven shocks, often exhibit unexpected enhancements in Fe/O and 3 He/ 4 He ratios—compositional signatures associated with impulsive flare events. The origin of these enrichments in GSEPs is still debated: shock reacceleration of preexisting suprathermal remnants versus freshly injected flare material. We investigate the relationship between GSEP composition and solar particle release (SPR) timing relative to electromagnetic radio signatures (type II and type III bursts) for 43 GSEP events selected from NOAA’s solar proton event (SPE) list. We determine SPR times using velocity dispersion analysis of Wind/LEMT helium intensities applying the self-starting CUSUM method, a novel approach for automated SEP onset detection. Compositional ratios derived from ACE/ULEIS and ACE/SIS are then compared as a function of relative SPR timing. Results show a clear relationship between SPR timing and composition: the strongest Fe and 3 He enhancements occur when SPR times are short relative to type III bursts and close to the earliest detectable type II emission, with 3 He/ 4 He reaching up to ∼46× solar wind values. Events with longer delays relative to either radio signature tend to display near–solar wind composition. We conclude that the timing of particle release relative to the eruption and early shock formation is a key factor in shaping GSEP composition.