Luminosity characteristics of the traveling current source return stroke models

A comparative analysis has been performed on the lightning channel-base current and the radiated light waveforms for five different return stroke models of the traveling current source type. It is assumed that the lightning current along the channel and the emitted light signals exhibit a linear relationship (direct proportionality) in their rising portions. Five return stroke models of the traveling-current-source-type are chosen and compared: the BG model, the classical TCS model, Diendorfer-Uman (DU) model, the modified Diendorfer-Uman (MDU) model and the generalized TCS model (GTCS). It is concluded that the channel discharge constant in the DU and the MDU models as well as the channel distribution function in the GTCS model have the decisive influence on the channel luminosity output. These findings support the idea of evaluating the variations of return stroke current along the lightning return stroke channel using light signals, provided that evaluation is limited to the rising portions of those signals and assuming that the light/current relationship observed at the bottom of the channel holds at other heights.