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| Titel |
Volume cross section of auroral radar backscatter and RMS plasma fluctuations inferred from coherent and incoherent scatter data: a response on backscatter volume parameters |
| VerfasserIn |
M. V. Uspensky, P. Janhunen  , A. V. Koustov, K. Kauristie |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 29, no. 6 ; Nr. 29, no. 6 (2011-06-22), S.1081-1092 |
| Datensatznummer |
250017042
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| Publikation (Nr.) |
 copernicus.org/angeo-29-1081-2011.pdf |
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| Zusammenfassung |
| Norway and Finland STARE radar measurements in the eastward auroral
electrojet are combined with EISCAT CP-1 measurements of the electron
density and electric field vector in the common scattering volume to
investigate the variation of the auroral radar volume cross section (VCS)
with the flow angle of observations (radar look direction with respect to
the E×B electron drift). The data set available consists of ~6000 points
for flow angles of 40–85° and electron drifts between 500
and 2000 m s−1. The EISCAT electron density N(h)-profile data are used
to estimate the effective electron density, aspect angle and thickness of
the backscattering layer. It is shown that the flow angle variation of the
VCS is rather weak, only ~5 dB within the range of the considered
flow angles. The VCS values themselves respond almost linearly to the square
of both the electron drift velocity magnitude and the effective electron
density. By adopting the inferred shape of the VCS variation with the flow
angle and the VCS dependence upon wavelength, the relative amplitude of
electrostatic electron density fluctuations over all scales is estimated.
Inferred values of 2–4 percent react nearly linearly to the electron drift
velocity in the range of 500–1000 m s−1 but the rate of increase slows
down at electron drifts >1000 m s−1 and density fluctuations of ~5.5
percent due to, perhaps, progressively growing nonlinear wave losses. |
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