Studies of lightning initiation

摘要

A long-standing question in lightning studies has concerned how lightning is initiated in thunderstorms, given the absence of physical conductors. Remote sensing observations of discharges are starting to provide the answer to this question, obtained in large part with radio frequency instruments and techniques. A recent important and unexpected step in this process has come from observations of the phenomenon called narrow bipolar events (NBEs) at NM Tech's mountain-top Langmuir Laboratory observatory in central New Mexico [1]. NBEs are fast, high current, short duration discharges that are the strongest natural sources of VHF radiation on earth [2]. They occur either in isolation from other discharges in a storm, or sometimes at the beginning of intracloud (IC) discharges [3, 4], but otherwise have eluded explanation for nearly four decades.