Study of multiple ELVES at the Pierre Auger Observatory

ROBERTO MUSSA; PIERRE AUGER COLLABORATION; M. GABRIELA NICORA

Conferencia; EGU General Assembly 2023; 2023

ELVES are transient ring-shaped emissions occurring in the ionosphere above thunderstorms.Multi-ELVES are events consisting of two and up to four rings of light separated temporally by tensof microseconds. The Fluorescence Detector (FD) at the Pierre Auger Observatory has beendetecting ELVES with a dedicated trigger since 2013. The high temporal resolution of 100 ns of theFD allows us to record the phototraces of the events in great detail. From the improved processingof the phototraces, we have observed ELVES with double and triple peaks. In fact, during theperiod 2014-20, about 27% of the events detected at Auger are multi-ELVES. The origin of multi-ELVES is still not fully understood, therefore in this work, we tested two models: the first onerelates the temporal difference between two peaks (ΔT) to the rise (tr) and fall (tf) times of thecurrent density pulse of the source beam; the second one relates the height of the intra-cloudlightning source (hb) to ΔT and is used to study events with three or more peaks. From the firstmodel, we can obtain combinations of tr and tf where ΔT tends to zero, i.e. the origin of the simpleELVES can also be explained. For this analysis, we compare the ELVES parameters measured inAuger with the lightning properties detected by Earth Networks, i.e. the location, waveform, andheight of these sources