HIGH-SPEED PHOTOGRAPHIC ANALYSIS OF INTRACLOUD LIGHTNING RADIATION-FIELDS

The radiation fields of 14 intracloud discharges have been analyzed. T he intracloud discharges are initiated by an upward moving predischarg e from the lower negative charge center propagating in steps and known as an L-change. The main discharge, known as a K-change, immediately follows the L-change and moves downwards from the upper positive charg e center with high velocity and luminosity. The durations of the flash es, and the L-change and K-change intervals, have been determined. The initial and very active portions of the L-change are found to contain nearly uniform pulses of radiation with a mean interval ranging from 2.9 to 7.5 ms. The corresponding value for the K-change is 4.8 ms. For L-changes the standard deviation ranges from 2.5-6.7 ms while for the K-change it ranges from 0.83-13.38 ms. The average charge destroyed b y an intracloud flash is 11.0 C while the average charge moment destro yed is 86.0 C km. The average step length and velocity for L-changes h ave been observed to be 108 m and 2.29 x 10(4) m/s respectively.