Connotea
CiteULike
del.ico.us
BibSonomyAbstract
Analysis of terrestrial thermospheric N2c′41Σu+(0) ∼b′1Σu+(1) −X1Σg+dayglow emission observed by the Far Ultraviolet Spectroscopic Explorer
Planetary and Space Science Division, Space Environment Technologies, Pasadena, California, USA
Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT, Australia
Planetary and Space Science Division, Space Environment Technologies, Pasadena, California, USA
Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT, Australia
Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland, USA
Terrestrial thermospheric dayglow emission from the coupled and overlapping c′4 1Σ u +(0) and b′ 1Σ u +(1) levels of molecular nitrogen, observed by the Far Ultraviolet Spectroscopic Explorer, is analyzed with the aid of a coupled channels quantum mechanical model of N2 spectroscopy and predissociation dynamics. Model emission spectra for the mixed c′4 1Σ u +(0) ∼ b′ 1Σ u +(1) − X 1Σ g +(v i = 2, 6–9) transitions, calculated for the case of excitation by photoelectron impact, are in excellent agreement with the observations. While the principal excitation mechanism for N2 in the thermosphere is photoelectron impact, evidence is also found in other transitions of resonant fluorescence, induced by lines in the solar atomic hydrogen Lyman series, atomic oxygen transitions, and other N2 bands. The observed emission rate of the c′4 1Σ u +(0) ∼ b′ 1Σ u +(1) − X 1Σ g +(0) band is ∼1% of that inferred from the emission rates to X 1Σ g +(v i > 2) levels. A qualitative explanation is given for the drastically reduced intensity and band shape distortion observed in the c′4 1Σ u +(0) − X 1Σ g +(0) emission band. Estimates of the total electron excitation rates for the nominal b′ 1Σ u +(1) and c′4 1Σ u +(0) levels are determined from the spectrum by extrapolating the model through regions containing unmeasured and/or resonantly absorbed bands.
Received 12 May 2008; accepted 2 February 2009; published 10 April 2009.
Citation: (2009), Analysis of terrestrial thermospheric N2c′41Σu+(0) ∼b′1Σu+(1) −X1Σg+dayglow emission observed by the Far Ultraviolet Spectroscopic Explorer, J. Geophys. Res., 114, D07304, doi:10.1029/2008JD010403.
Cited By