Needle Propagation and Twinkling Characteristics

Recently, a new lightning phenomena, termed needles, has been observed in both VHF and optical along positive leaders. They appear as small (<100 m) leader branches that undergo dielectric breakdown at regular intervals (called twinkles). Providing coherent consistent explanation for this phenomenon is challenging each twinkle form of negative propagates away from the leader. In study, we provide detailed observations needles VHF, during two flashes. We show distributions different needle properties, including propagation speeds, time between twinkles, lengths, among others. return stroke multiple recoil leaders quench activity. also nearby activity does not seem to correlate together, twinkling can slow down by 10%–30% per twinkle. conclude presenting possibilities how could induce channel, argue twinkles propagate like stepped or depending on temperature needle, which implies probably without emitting VHF.