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The opacity of lightning

1965; American Geophysical Union; Volume: 70; Issue: 22 Linguagem: Inglês

10.1029/jz070i022p05491

2156-2202

M. A. Uman, Richard E. Orville,

Lightning and Electromagnetic Phenomena

Journal of Geophysical Research (1896-1977)Volume 70, Issue 22 p. 5491-5497 The opacity of lightning Martin A. Uman, Martin A. UmanSearch for more papers by this authorRichard E. Orville, Richard E. OrvilleSearch for more papers by this author Martin A. Uman, Martin A. UmanSearch for more papers by this authorRichard E. Orville, Richard E. OrvilleSearch for more papers by this author First published: 15 November 1965 https://doi.org/10.1029/JZ070i022p05491Citations: 51AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract Lightning channels studied are shown to be optically thin to two N II multiplets by comparing the relative intensities of multiplet members with the predictions of theory and with previous laboratory measurements. From this result it is shown that the lightning channels studied are optically thin to all measured N II and O II line radiation and to the high-temperature continuum. The absorption coefficient for N II 4630.5 A is calculated. From this calculation and the requirement of optical thinness, the effective diameter within which the radiating N II atoms are contained is determined to be less than a few millimeters. The opacity of the lightning channel to neutral atom radiation and to the low-temperature continuum is considered. The results of a paper by Zhivlyuk and Mandel'shtam in which the lightning channel is assumed to be optically thick to three N II lines and one O II line are discussed. References Gilmore, F. R., Energy levels, partition functions, and fractional electronic populations for nitrogen and oxygen atoms and ions to 25,000°KRand Corp. Mem. RM-3748-PRAugust, 1963. Griem, H. R., Plasma Spectroscopy, McGraw-Hill Book Company, New York, 1964. Mandel'shtam, S. L., Excitation of the spectrum in a spark discharge, Spectrochim. Acta, 15, 255–271, 1959. Mastrup, F., W. Wiese, Experimentelle Bestimmung der Oszillatorenstärken einiger NII-und OII-Linien, Z. Astrophys., 44, 259–279, 1958. Prueitt, M. L., The excitation temperature of lightning, J. Geophys. Res., 68, 803–811, 1963. Salanave, L. E., R. E. Orville, C. N. Richards, Slitless spectra of lightning in the region from 3850 to 6900 angstroms, J. Geophys. Res., 67, 1877–1884, 1962. Spitzer Jr., L., R. Harm, Transport phenomena in a completely ionized gas, Phys. Rev., 89, 977–981, 1953. Uman, M. A., The peak temperature of lightning, J. Atmospheric Terrest. Phys., 26, 123–128, 1964a. Uman, M. A., The conductivity of lightning, J. Atmospheric Terrest. Phys., 26, 1215–1219, 1964b. Uman, M. A., R. E. Orville, Electron density measurement in lightning from Stark-broadening of Hα, J. Geophys. Res., 69, 5151–5154, 1964. Uman, M. A., R. E. Orville, L. E. Salanave, The density, pressure and particle distribution in a lightning stroke near peak temperature, J. Atmospheric Sci., 21, 306–310, 1964a. Uman, M. A., R. E. Orville, L. E. Salanave, The mass density, pressure, and electron density in three lightning strokes near peak temperature, J. Geophys. Res., 69, 5423–5424, 1964b. Zhivlyuk, Yu. N., S. L. Mandel'shtam, On the temperature of lightning and the force of thunder, English Transl., Soviet Phys. JETP, 13, 338–340, 1961. Citing Literature Volume70, Issue2215 November 1965Pages 5491-5497 ReferencesRelatedInformation