Accession Number : AD0015456


Title :   EMISSION IN THE HYDROGEN BALMER LINES AND CONTINUUM IN THE FLASH SPECTRUM OF THE 1952 TOTAL SOLAR ECLIPSE AT KHARTOUM, SUDAN


Corporate Author : HIGH ALTITUDE OBSERVATORY BOULDER CO


Personal Author(s) : Athay, Russell G ; Billings, Donald E ; Evans, John W ; Roberts, Walter O


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/015456.pdf


Report Date : 13 Jul 1953


Pagination or Media Count : 114


Abstract : The analysis of UV spectrograms of the chromospheric flash was hindered since the UV standardizing exposures were unsatisfactory as a result of a failure of the film-advance mechanism. Characteristic curves from standard lamp exposures were useful principally as first approximations to the curves representing eclipse spectrograms. In addition, exposure-duration uncertainties existed on all except 6 spectrograms. However, methods were developed which allowed reliable determinations of the characteristic curves of the eclipse films; a satisfactory independent check was made of the consistency and accuracy of the final curves. The H-Balmer-line densities from H8 to H31 at 4 wave lengths in the Balmer continuum were measured at 2 points on the limb on 17 spectrograms at second contact. Tables are included of 24 corrected line intensities of the Balmer series at 108-km height separations in the lower chromosphere over the range from 100 to 3800 km. The Balmer decrements agreed well with those of the 1932 eclipse at chromosphere heights where observations overlap. The emission-height gradients of H are about 40% larger than in 1932, and the absolute intensities of the H emission at the chromosphere base are about 5 times as large as those in 1932. Preliminary results indicated pronounced self-absorption effects and large departures from thermodynamic equilibrium at 700 km and greater heights. Electron temperature was less than 12,000 k below 1000 km and increased at greater heights. Electron densities in the low chromosphere were of the order of 10 to the eleventh power/cc.


Descriptors :   *CHROMOSPHERE , *SOLAR SPECTRUM , ELECTRON DENSITY , INTENSITY , ACCURACY , EQUILIBRIUM(GENERAL) , ECLIPSES , APPROXIMATION(MATHEMATICS) , OVERLAP , SPECTROGRAPHY , THERMODYNAMICS , ULTRAVIOLET RADIATION , ELECTRON ENERGY


Subject Categories : Astronomy
      Atomic and Molecular Physics and Spectroscopy


Distribution Statement : APPROVED FOR PUBLIC RELEASE