Diagnosing the lightning plasma temperature based on the collisional-radiative model

Abstract

Energy levels, transition probabilities, collision sections, and collision excitation rate coefficients of NII ion have been calculated using Flexible Atomic Code, which is based on the multiconfiguration Dirac–Fock method. The ratios of line intensity, I_567.96 nm/I_500.52 nm, where the 567.96 and 500.52 nm are two strong spectral lines from the core current channel of lightning, have been calculated by using the collisional-radiative model, in which the line intensity is proportional to the collision excitation rate coefficients from the ground state to the excited state and the transition probability from the high excited state to the low excited state. The temperatures of six lightning plasma channels were then obtained, and they are consistent with temperatures obtained by diagnosing the actual spectrum with the multispectral line method.