Model calculation of atmospheric emission caused by energetic O[sup +] precipitation

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/93JA01148· OSTI ID:7064895

Ishimoto, M ^[1]; Romick, G J; Meng, C I ^[2]

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1. Computational Physics Inc., Fairfax, VA (United States)
2. Johns Hopkins Univ., Laurel, MD (United States)

Some anomalous auroral emissions, typically observed below 60[degrees] geomagnetic latitude during large geomagnetic storms, have distinctive spectral characteristics, that have been attributed to energetic ion/neutral particle precipitation. Mass spectrometers on satellites have observed energetic (keV) ion and neutral precipitation (up to 30 erg cm[sup [minus]2] s[sup [minus]1]) below 60[degrees] geomagnetic latitude. In this study the authors used a model to calculate emissions with the characteristics of the incident O[sup +] energy spectra observed from satellites and compared the emission intensities and intensity ratios of the model calculation to those from the anomalous auroral emission spectra. Using an oxygen transport model with estimated emission cross sections, they calculated the emission altitude distributions, vertically integrated column emission intensities and the spectral profile of atomic oxygen line emissions. The calculated emissions were for the N[sup +][sub 2] and O[sup +][sub 2] first negative(1N), N[sub 2] second positive(2P), and N[sub 2] Lyman-Birge-Hopfield (LBH) bands; the N I lines at 1493, 1744, and 8680[angstrom]; the N II line at 5005[angstrom], and the O I lines at 1304, 1356, and 6300[angstrom]. Most atomic oxygen line emissions are from primary oxygen atoms traveling downward at a speed of 10[sup 7] and 10[sup 8] cm s[sup [minus]1]. Because of the high speed at which the atoms travel most [sup 1]D is quenched before emission. Atomic oxygen line spectra at 1304 and 1356[angstrom] displays a 1[angstrom] Doppler shift and some broadening if viewed from above or below. The emission altitudes and intensities are most sensitive to the choice of elastic scattering cross sections and emission cross sections, respectively. 24 refs., 5 figs., 7 tabs.

• OSTI ID: 7064895
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 99:A1; ISSN JGREA2; 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
AURORAE
CHARGED PARTICLES
CHARGED-PARTICLE PRECIPITATION
ELEMENTS
EMISSION SPECTRA
IONS
NITROGEN
NONMETALS
OXYGEN
OXYGEN IONS
SPECTRA