HR: 1340h
AN: SM23A-0492    [Abstracts]
TI: Using Radars in Place of Magnetometers: Detection and Properties of Pc3-5 Wave Fields in HF Radar Data
AU: Ponomarenko, P
EM: phpp@alinga.newcastle.edu.au
AF: University of Newcastle, School of Mathematical and Physical Science, Callaghan, NSW 2308 Australia
AU: * Menk, F W
AF: University of Newcastle, School of Mathematical and Physical Science, Callaghan, NSW 2308 Australia
AU: Waters, C L
EM: colin.waters@newcastle.edu.au
AF: University of Newcastle, School of Mathematical and Physical Science, Callaghan, NSW 2308 Australia
AB: SuperDARN HF radars are usually used to examine HF echoes from field-aligned ionospheric irregularity structures. However, ground scatter is also often recorded. Because the ground scatter signal is reflected from the ionosphere its Doppler shift is a sensitive indicator of ionospheric motions. We have used the TIGER radar, which operates at relatively low latitudes, to examine ground scatter returns with high time resolution. Ground scatter returns are present virtually every day and wave-like Doppler shift features are evident almost each time. Comparison with ground magnetometer data shows that these are the ionospheric signature of downgoing ULF waves. Several different types of wave features have been observed, including very large scale Pc5, harmonics of field line resonances in the Pc3-4 range, and bandlimited Pc4 at night. This paper presents examples and discusses the wave generation and propagation mechanisms. Furthermore, estimates of the ionospheric transfer function over the 10-110 mHz range are compared with results of numerical and analytical modelling.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2439 Ionospheric irregularities
DE: 2772 Plasma waves and instabilities
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting