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GEOPHYSICAL RESEARCH LETTERS,
VOL. 32,
L05108,
doi:10.1029/2004GL020737,
2005
Strong evidence for gravity wave seeding of an ionospheric plasma instability
Michael J. Nicolls
School of Electrical and Computer Engineering, Cornell University, Ithaca, New York, USA
Michael C. Kelley
School of Electrical and Computer Engineering, Cornell University, Ithaca, New York, USA
Abstract
Here we present evidence for gravity wave seeding of ionospheric plasma instabilities. On October 2, 2002 a series of magnetic
substorms led to a large-scale traveling ionospheric disturbance (LSTID) that was detected by the Arecibo incoherent scatter
radar. Several large oscillations of the F layer occurred, including one that lifted the layer to over 450 km. At least two shorter period oscillations were identified
in the plasma contours along the bottomside of the layer. The largest amplitude signal exhibited a downward phase velocity,
vertical wavelength, and period (∼50 minutes) consistent with the linear theory of gravity waves. A ∼30-minute period oscillation
was amplified considerably when the bottomside was lifted to high altitudes near dawn. This amplification was likely due to
a gravitational instability with a growth time of about 15 minutes. We believe that the LSTID created conditions conducive
to instability, while the shorter period waves created the seed irregularities.
Received 14
June
2004;
accepted 8
February
2005;
published 10
March
2005.
Index Terms: 2439 Ionosphere: Ionospheric irregularities; 2437 Ionosphere: Ionospheric dynamics; 2435 Ionosphere: Ionospheric disturbances; 2471 Ionosphere: Plasma waves and instabilities (2772).
Read Full Article (file size: 330699 bytes) Cited by
Citation: Nicolls, M. J., and M. C. Kelley
(2005),
Strong evidence for gravity wave seeding of an ionospheric plasma instability,
Geophys. Res. Lett.,
32,
L05108,
doi:10.1029/2004GL020737.
Copyright 2005 by the American Geophysical Union.
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