RESUMEN
A laser induced breakdown spectroscopy experiment was carried out using Nd:YAG laser in air, and time-resolved spectra were measured. Based on local thermodynamic equilibrium assumption, a method used to simulate LIBS spectra is proposed. A LIBS spectrum of air in the wavelength range of 700~900 nm was simulated using this method. A good agreement between experiment and simulation was obtained, and moreover, the relative concentrations of the N, O and Ar in air were obtained.
RESUMEN
Spectra of return strokes for artificial triggered lightning were obtained by optical multi-channel analyzer (OMA) in Shandong region. Compared with previous spectra of natural lightning, additional lines of ArI 602.5 nm and ArII 666.5 nm were observed. Under the model of local thermodynamic equilibrium, electronic temperatures of the lightning channel plasma were obtained according to the relative line intensities. Meanwhile, with semi-empirical method the electron density was obtained by Halpha line Stark broadening. In combination with plasma theory, electrical conductivity of the lightning channel has been calculated for the first time, and the characteristic of conductivity for lightning channel was also discussed. The relation between the electrical conductivity of channel and the return stroke current was analyzed, providing reference data for further work on computing return stroke current. Results show that the lightning channel is a good conductor, and electrons are the main carrier of channel current. The brightness of artificial triggered lightning channel is usually higher than that of natural lightning, and its current is smaller than that of the natural lightning.