Determination of ionospheric conductivities from FUV auroral emissions
- Univ. of Alabama, Huntsville, AL (United States)
- NASA Marshall Space Flight Center, Huntsville, AL (United States)
The purpose of this paper is to examine the viability of using N{sub 2} Lyman-Birge-Hopfield (LBH) emission ratios to infer auroral conductances and to quantify the strengths and weaknesses of this technique. The authors show that column-integrated Hall and Pedersen conductances may be determined from a single remote measurement of a pair of auroral LBH emissions, one in the region of strong O{sub 2} absorption (1464 {angstrom}) and one lying outside of this region (1838 {angstrom}). The dependence of the determined conductivities on incident average energy, total energy flux, and changes in solar and magnetic activity levels is examined. They show that, for energies above 5 keV, auroral conductances may be scaled by the square root of the incident energy flux with errors less than about 20%. For lower energies, however, the scaling may deviate significantly from a power of 0.5. The authors provide appropriate scaling factors as a function of average energy. They also note that the choice of either a Gaussian or Maxwellian distribution can significantly affect low-energy (<1 keV) conductance calculations. Finally, they quantify the conditions under which the mean energy of a Gaussian energy distribution may differ significantly from the characteristic energy. 46 refs., 10 figs., 1 tab.
- OSTI ID:
- 91314
- Journal Information:
- Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A12 Vol. 99; ISSN JGREA2; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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