Fractal dynamics analysis of the VHF radiation pulses during initial breakdown process of lightning

Abstract

This paper presents the first analysis of fractal dynamics of lightning initiation process with a coherent approach. Using experimental data obtained from a broadband interferometer system operating at a bandwidth of 25-100 MHz, the sequences of inter-pulse time interval of the VHF radiation pulses emitted during the lightning initial breakdown process were analyzed with the multifractal detrended fluctuation analysis (MF-DFA) method. For 63 lightning flashes analyzed, it was found that there is an apparent long-range time correlated and nonlinear cascade behavior within the initiation breakdown process of the lightning. This result suggests that the initiation of lightning may be associated with progressively building up of correlated strong electrical field regions by self-similar scaling up (inverse cascading) of discharges across scales from small to large. The result may be promising toward our understanding of lightning initiation.