Diagnosing the electron density of channel plasma in artificially triggered lightning

Abstract

Transition rates, collision excitation cross sections, and collision excitation rate coefficients of neutral N I atom and N II ions were calculated by Flexible Atomic Code that is based on the multiconfiguration Dirac-Fock method. The line intensity of some strong spectral lines were calculated. Then the dependent relationship among the ratio of line intensity I′I, the electron density ne and the electron temperature T were obtained. The calculation shows that the electron density has some dependence on the temperature and the ratio of line intensity. Furthermore, through applying the theoretical calculations to the channel plasma spectra of artificially triggered lightning, the electron densities were diagnosed at different channel locations and times. The accuracy of the electron density was estimated using the degree of accordance, which can pick out the diagnostic data that can best reflect the real state of plasma from a large number of statistical data.