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Large airglow enhancements produced via wave‐plasma interactions in sporadic E
Author(s) -
Djuth F. T.,
Bernhardt P. A.,
Tepley C. A.,
Gardner J. A.,
Kelley M. C.,
Broadfoot A. L.,
Kagan L. M.,
Sulzer M. P.,
Elder J. H.,
Selcher C.,
Isham B.,
Brown C.,
Carlson H. C.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900296
Subject(s) - airglow , ionosphere , thermosphere , plasma , physics , flux (metallurgy) , electron , atmospheric sciences , f region , atomic physics , sporadic e propagation , geophysics , materials science , quantum mechanics , metallurgy
In the past there has been great interest in monitoring enhanced 557.7 nm O(¹S) emissions from the thermosphere in connection with high‐power, high‐frequency (HF) radio wave modification of the F region ionosphere. These emissions are considered to be evidence that the HF‐modified electron distribution function is non‐Maxwellian because a significant flux of ∼5–6 eV electrons is required to produce the airglow. The suprathermal tail is believed to develop as a result of nonlinear plasma processes. Past F region observations of 557.7 nm airglow at Arecibo Observatory, Puerto Rico have yielded only a few Rayleighs of enhanced emissions. Recently, airglow enhancements were monitored in sporadic E above Arecibo. Surprisingly, these experiments yielded ∼55 Rayleighs of enhanced 557.7 nm airglow and the first observations of emissions from the N 2 first positive molecular bands. The observations imply that a large flux of energetic (5–10 eV) electrons is generated as part of the wave‐plasma interaction in sporadic E .