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Volcanic lightning in nature and in the lab.
Electrical discharges in explosive eruptions can provide crucial information on the dynamics and structure of volcanic plumes. We performed multi-parametric monitoring of volcanic lightning at Sakurajima volcano (Japan) and generated discharges in particle-laden jets in the lab. Observations at Sakurajima allow the measurement of flash properties with respect to the plume evolution as well as magnetic- and electric-field variation and associated transferred current. We complement field observations with decompression experiments of ash samples and analogue materials. Experiments show many similarities with nature and, most importantly, they show how lightning is controlled by the dynamics of the rapidly expanding particle-laden jet.