Solar Lyman Series Line Profiles and Atomic Hydrogen Excitation Rates

Abstract

view Abstract Citations (28) References (22) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Solar Lyman Series Line Profiles and Atomic Hydrogen Excitation Rates Meier, R. R. Abstract The atomic hydrogen Lyman series lines on the Sun were observed in high spectral resolution (0.14 A) during a Naval Research Laboratory sounding rocket flight in 1962 August, a period of low solar activity. The spectral fluxes which had not been previously published reveal strong intrinsic reversal of the Lyα and Lyβ lines, but Gaussian shaped lines are seen for Lyman 3-10. Placing the line fluxes on an absolute scale through use of independent measurements allows the calculation of excitation rates which are applicable to planetary and interplanetary hydrogen atoms. In these calculations, the effect of cascade was evaluated with a detailed model of the branching rates following Lyman series excitation. Application of the calculated excitation rates to measurements of Baα emission in the terrestrial nightglow shows that emission lines arising from the 3 2S and 3 2D states can contribute 6.4% and 0.7% of the total emission, respectively, with the remainder resulting from fluorescence from direct Lyβ excitation of the 3 2P state. These results are consistent with ground-based observations which show line reddening with an excess intensity of 10%±5% relative to that expected from Lyβ excitation of the 3 2P state of hydrogen. Publication: The Astrophysical Journal Pub Date: October 1995 DOI: 10.1086/176318 Bibcode: 1995ApJ...452..462M Keywords: ATMOSPHERIC EFFECTS; ATOMIC PROCESSES; LINE: PROFILES; SUN: UV RADIATION full text sources ADS | Related Materials (1) Erratum: 1996ApJ...468..455M