Decrease in the Intensity of Hydrogen Lines in the Solar Chromosphere

Abstract

ROUSE1,2 has recently tried to explain the decreasing intensities of the high Balmer and Paschen lines in the solar atmosphere with his theory for the hydrogen atom which includes a complete screened Coulomb potential. Rouse's theory takes into account the fact that the volume occupied by a hydrogen atom (and thus the maximum possible value of the principal quantum number n) is limited by the presence of nearby atoms. He has cited observations of the highest lines visible in the photosphere and chromosphere and statements by Ivanov-Kholodnyi and Nikol'skii3 that “in prominence and chromospheric spectra, it has been found that near the series limit the lines do not merge because of their broadening and convergence, but instead they disappear because of a rapid fall in intensity” and “the problem of the drop in line intensity toward the series limit has not been solved so far”. The parts of the quoted statements relating to the chromosphere are ultimately based on the 1952 eclipse data of Athay et al.4. Although the theory of Rouse concerning the limiting value of n is certainly expected to apply to the chromosphere, my purpose here is to question whether present chromospheric observations confirm the theoretical limit on n and whether the variation of the high chromospheric hydrogen lines is anomalous.