VLF/ELF sferic evidence for in-cloud discharge activity producing sprites



[1] Sprite luminosities produced by winter lightning in Japan were found to be associated with simultaneous occurrences of clusters of radio atmospherics as observed in the VLF range, suggesting an in-cloud discharge activity. Concurrent ELF data show transient perturbations, indicating continuous charge transfer in causative lightning. These data provide the first evidence that an in-cloud discharge activity plays an important role in the generation mechanism of sprites.