Characteristics of auroral electron precipitation derived from optical spectroscopy

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA094iA06p06799· OSTI ID:5939980

Rees, M H; Lummerzheim, D

Electron impact excitation of auroral spectral features in the visible and ultraviolet are computed by solving the complete electron transport equation. Excitation rates are given for several bands of N/sub 2/ (A /sup 3//Sigma/, B /sup 3//Pi/, W /sup 3//Delta/, a /sup 1//Pi/, C /sup 3//Pi/) and of N/sub 2//sup +/, for bands of O/sub 2/ (a /sup 1//Delta/, b /sup 1//Sigma/) and of O/sub 2//sup +/, and for several states of O (/sup 1/D, /sup 1/S, /sup 5/S, /sup 3/S) and of O/sup +/. The theoretical results are tested by comparing the predicted emission rate ratios N/sub 2/ 2PG(0,0)/N/sub 2//sup +/ 1NG(0,1) to ratios derived from photometer measurements of I(3371 A) and I(4278 A) that were acquired over many hours of observations from a high-flying aircraft. The observations spanned a wide range of auroral types that were ordered by their electron spectral hardness. The results show that the ratio I(3371 A)/I(4278 A) is a better indicator of the characteristic energy of the electron spectrum than the so-called ''red to blue'' ratio, I(6300 A)/I(4178 A), which has been used over the years. Results of observations of the I(3371 A)/I(4278 A) ratio acquired by rocket-borne photometers, by satellite borne photometers and by a spectrometer show poor agreement with the airborne experimental results and with the model predictions. Significant differences between the model results reported here and previously published predictions of this spectroscopic ratio are also noted. A relationship between the energy flux and the characteristic energy of electron precipitation, first reported by Eather and Mended (1972), is found to hold over a wide range of fluxes. /copyright/ American Geophysical Union 1989

• Research Organization: Geophysical Institute, University of Alaska, Fairbanks (US)
• OSTI ID: 5939980
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 94:A6; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
CHARGED PARTICLES
CHARGED-PARTICLE PRECIPITATION
ELECTRON PRECIPITATION
ELECTRON SPECTRA
ELECTRONS
ELEMENTARY PARTICLES
ENERGY-LEVEL TRANSITIONS
EQUIPMENT
EXCITATION
FERMIONS
FLUCTUATIONS
IONS
LEPTONS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
NITROGEN IONS
OPTICAL EQUIPMENT
OXYGEN IONS
PHOTOMETERS
SPECTRA
SPECTROSCOPY
VARIATIONS