Evaluation of the Existence of Initial Breakdown Process for Cloud-to-Ground Flashes

Abstract

In this paper, we are motivated to evaluate the existence of Initial Breakdown (IB) process in Cloud-to-Ground (CG) flashes of a tropical storm by using both broadband E-field and B-field antenna systems. It is important to note here that all previous studies were using only broadband E-field antenna system. In this study, the evaluation of existence of IB process was done based on both broadband E-field and B-field antenna systems. The data of lightning flashes were collected on June 3rd 2016 by our station in Malacca, Malaysia. We analyzed 50 CG flashes from a tropical storm happened in Kuala Lumpur area. The data recorded by broadband E-field antenna system shows that 94% of CG flashes were preceded by IB process. On the other hand, by using B-field antenna system, all CG flashes have been observed to be preceded by IB process. This finding is very significant because we can conclude that all CG flashes are initiated by IB process. The average pulse duration of the first, second, third, and the largest IB pulses are $33.52 {\mu } \mathrm {s} , 36.08 {\mu } \mathrm {s}$, 37.76 μs, 43.02 μs, respectively. The average peak amplitude of the first, second, third, and the largest IB pulses are 179.60 mV, 261.90 mV, 272.94 mV, 609.57 mV, respectively.