Some properties of em radiation from lightning

Abstract

Simultaneous records of electrostatic fields and optical and HF (10 MHz) radiation from ground and cloud flashes occurring in Suva, Fiji, have been made, and gaps (brief cessations) in the HF radiation from lightning discharges have been analyzed. Gaps in the HF noise following return strokes appear to be terminated by K changes, the gap duration distribution following closely that of previously observed K change interval distributions. These observations support conjecture that in‐cloud junction streamers, rather than ceasing immediately following a return stroke, proceed from the top of the return stroke channel until a pocket of charge is tapped to produce the K change which terminates the noise gap. The streamer itself is presumed to radiate HF only weakly. Earlier proposals that HF noise gaps of duration greater than a certain length are associated with return strokes and therefore can be used to discriminate, for lightning counting purposes, between cloud‐ground discharges and intracloud discharges are not supported.