Comparison of Modeled and Measured High-Resolution Optical Spectra from Lightning

Monday, 15 December 2014
Jarrod Douglas Edwards1, Philip Dreike1, Mark William Smith1, Anthony Tanbakuchi1, Joshua David Zollweg1 and John Zinn2, (1)Sandia National Laboratories, Albuquerque, NM, United States, (2)Los Alamos National Laboratory, Los Alamos, NM, United States
High-resolution modeling of the optical spectra generated by lightning is useful for identification, characterization, and discrimination of a lightning discharge. We have produced resolution at a 1 Angstrom scale in photon wavelength by generating opacities as a function of density, temperature, and photon energy. We use this data with a 1-D cylindrical radiation-hydrodynamics model to compute the physical parameters, e.g. density and temperature, of a lightning stroke. By characterizing the spatial distribution of the density and temperature inside the lightning channel, in conjunction with these high-resolution opacities, we are able to identify the region from which the observable optical spectrum is emitted. We model this spectrum in detail for visible wavelengths over the range of approximately 400-700 nm, identifying key features in the spectrum. We present the results of this model and compare them with measured data that we acquired using a high speed slit-less spectrometer.