Hydrogen concentration in lightning plasma channel and its effect on discharge characteristics

Abstract

By contrastive analysis on the spectra of cloud-to-ground (CG) lightning and those of laboratory long air gap discharge and laser-induced breakdown air, the effect of hydrogen concentration on current intensity in lightning plasma channels was analyzed. It is found that, in CG lightning spectra, the lines from hydrogen atom have a relative higher intensity and longer duration. Based on plasma diagnostic theory, the temperature and its time evolution of discharge channel was calculated. The radii of core current-carrying channel and corona channel of natural lightning were obtained, as well as peak current. It is inferred that the atomic spectral lines with lower excitation energy can reflect the radiation characteristics of the surrounding corona channel. The particle concentrations in the channels were calculated using a free calibration quantitative analysis method. A strong positive correlation among hydrogen atom concentration, peak current, and the corresponding corona channel radius was obtained. This property shows that hydrogen concentration in lightning plasma channels can reflect the discharge current intensity primely, which can be regarded as an important parameter to characterize the discharge characteristics of natural lightning. The factors that affect the discharge characteristics of natural lightning are very complex. From the above results, it is deduced that air humidity is a potential factor affecting the lightning discharge characteristic.