Particle bursts in the inner radiation belt related to global lightning activity

Particle bursts (PBs), the phenomena characterized by short-term increases of particle counting rates (CRs), were observed by space-borne radiation belt particle detectors. With the electron CR data obtained by National Oceanic and Atmospheric Administration (NOAA)-18 satellite, the occurrence of PBs in the inner belt (1?L?2 and B?20.5 μT) were derived for years 2006–2011. The monthly occurrence number of PBs exhibits a strong maximum in northern summer (May–August). In association with global lightning data, the seasonal occurrence of PBs is found to be consistent with the lightning activity, especially if only lightning flashes at latitudes >20° are taken into account. The positive correlation between PBs and mid-latitude lightning discharges indicates the role of lightning-induced whistler waves, and is consistent with the expected pitch-angle scattering by wave-particle interactions. The contribution of lightning is so significant that it forms a non-negligible seasonal background of PBs. If one connects PBs to seismoelectromagnetic emissions (SEME) in attempt to find the earthquake precursor, the lightning background needs to be considered with great care.