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A case study of HF radar spectral width in the post midnight magnetic local time sector and its relationship to the polar cap boundary

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journal contribution
posted on 17.10.2013, 11:20 by Emma E. Woodfield, J. A. Davies, P. Eglitis, M. Lester
The aim of this paper is to advance the current understanding of the spectral width parameter observed by coherent high frequency (HF) radars. In particular, we address the relationship of a frequently observed gradient, between low ( < 200 m/s) and high ( > 200 m/s) spectral width, to magnetospheric boundaries. Previous work has linked this gradient in the spectral width, in the nightside sector of magnetic local time, to the Polar Cap Boundary (PCB), and also to the boundary between the Central Plasma Sheet (CPS) and the Plasma Sheet Boundary Layer (PSBL). The present case study investigates the former by comparison with the 630.0 nm optical emission. No suitable data were available to test the second of the two hypotheses. It is found that during the interval in question the spectral width gradient is within the region of the 630.0 nm optical emission. A comparison of coherent and incoherent scatter radar data is also conducted, which indicates that values of high spectral width are typically collocated with elevated F-region electron temperatures. We conclude that the high spectral width region in the interval under study is associated with particle precipitation and also that the spectral width gradient is not a reliable method for locating the PCB.

History

Citation

ANNALES GEOPHYSICAE, 2002, 20 (4), pp. 501-509

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

ANNALES GEOPHYSICAE

Publisher

European Geosciences Union (EGU)

issn

0992-7689

eissn

1432-0576

Copyright date

2002

Available date

17/10/2013

Publisher version

http://www.ann-geophys.net/20/501/2002/angeo-20-501-2002.html

Language

en