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Ann. Geophys., 20, 1487-1498, 2002
www.ann-geophys.net/20/1487/2002/
© European Geosciences Union 2002
Morning sector drift-bounce resonance driven ULF waves observed in artificially-induced HF radar backscatter
L. J. Baddeley1, T. K. Yeoman1, D. M. Wright1, J. A. Davies1, K. J. Trattner2, and J. L. Roeder3
1Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK
2Lockheed Martin ATC, Palo Alto, USA
3The Aerospace Corporation, Los Angeles, CA, USA
Correspondence to: L. J. Baddeley
(Lisa.Baddeley@ion.le.ac.uk)
Abstract. HF radar backscatter,
which has been artificially-induced by a high power RF facility such as the
EISCAT heater at Tromsø, has provided coherent radar ionospheric electric
field data of unprecedented temporal resolution and accuracy. Here such data
are used to investigate ULF wave processes observed by both the CUTLASS HF
radars and the EISCAT UHF radar. Data from the SP-UK-OUCH experiment have
revealed small-scale (high azimuthal wave number, m <approx> -45)
waves, predominantly in the morning sector, thought to be brought about by the
drift-bounce resonance processes. Conjugate observations from the Polar
CAM-MICE instrument indicate the presence of a non-Maxwellian ion distribution
function. Further statistical analysis has been undertaken, using the Polar
TIMAS instrument, to reveal the prevalence and magnitude of the non-Maxwellian
energetic particle populations thought to be responsible for generating these
wave types.
Key words. Ionosphere (active
experiments; wave-particle interactions) Magnetospheric physics (MHD waves and
instabilities)
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