CHARACTERISTICS OF LARGE PULSES OF RADIATED FIELDS FROM CLOUD FLASH DISCHARGES*

Observations show that the sequences of microsecond-scale pulses are produced in cloud flash discharge processes.In the present work we report on measurements of larger bipolar pulses(LBP)of the radiation fields which are classified into four types according to their waveshapes and polarities of initial peak.Either positive or negative pulse contains two kinds of waveshapes:one with a smooth rise and the other with 2 or 3 fast-rising pulse superimposed on the initial half cycle.The pulse waveshape characteristics in both time and frequency domains are as follows.Among 2908 samples there are 45% of the positive polarity and 55% of the negative polarity.The positive pulses tend to have distinctly smaller values than negative pulses in rise time,half width and zero-crossing time of the initial peak.The peaks of positive pulse spectra tend to occur at a higher frequency than those of negative pulses.Despite differences above,positive and negative pulses have a similar total duration.