Hydrogen Balmer alpha intensity distributions and line profiles from multiple scattering theory using realistic geocoronal models

Journal Article · Wed Jul 01 04:00:00 EDT 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA07p07619· OSTI ID:5398512

Anderson, Jr, D E; Meier, R R ^[1]; Hodges, Jr, R R; Tinsley, B A ^[2]

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1. Naval Research Lab., Washington, DC (United States)
2. Univ. of Texas, Richardson (United States)

The H Balmer {alpha} nightglow is investigated by using Monte Carlo models of asymmetric geocoronal atomic hydrogen distributions as input to a radiative transfer model of solar Lyman {beta} radiation in the thermosphere and exosphere. The radiative transfer model includes all orders of scattering, temperature variation with altitude and solar zenith angle, and anisotropic velocity distributions. The influences of multiple scattering of Lyman {beta} radiation and of observing geometry on the H Balmer {alpha} intensity and effective temperature are evaluated in detail. Morning and evening hydrogen distributions for minimum, medium, and maximum solar activity are used in calculations of nightglow emission rates and line profiles. For each of the hydrogen models the H Balmer {alpha} intensity and effective temperature are displayed as a function of solar depression angle, observation zenith angle, and azimuth relative to the sun, to make possible detailed comparison to observations. Except for rather unique observing conditions, multiple scattering effects cannot be ignored for the determination of either intensity or temperature. Observed effective temperatures which are significantly less than the exobase temperature may be due either to low-altitude thermospheric hydrogen or to high-altitude exospheric hydrogen and depend on the observing conditions and the level of solar activity. Previous (selected) observations of the H Balmer {alpha} nightglow and effective temperatures are compared to models which most closely represent the solar conditions of the observations. Results of the theoretical investigation of H Balmer {alpha} emissions and of model-data comparisons indicate that predicted morning-evening concentration variations yield small intensity variations for solar depression angles greater than 20{degree}.

• OSTI ID: 5398512
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 92:A7; ISSN JGREA; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AIRGLOW
ANISOTROPY
BALMER LINES
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
DAILY VARIATIONS
DISTRIBUTION
EARTH ATMOSPHERE
ELEMENTS
EVALUATION
GEOGRAPHICAL VARIATIONS
HYDROGEN
LATITUDE EFFECT
MATHEMATICAL MODELS
MONTE CARLO METHOD
NONMETALS
SCATTERING
SOLAR ACTIVITY
SPATIAL DISTRIBUTION
THERMOSPHERE
VARIATIONS