A comparison of EISCAT and HF Doppler observations of a ULF wave

International audience Since the middle of 1995, an HF Doppler sounder has been running almost continuously in northern Norway, with the receiver at Ramfjordmoen and the transmitter at Seljelvnes. Concurrent operation of the EISCAT UHF radar in common programme (CP-1) mode has made it possible to st...

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Bibliographic Details
Main Authors: Wright, D. M., Yeoman, T. K., Davies, J. A.
Other Authors: Department of Physics and Astronomy Leicester, University of Leicester
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 1998
Subjects:
Online Access:https://hal.science/hal-00316447
https://hal.science/hal-00316447/document
https://hal.science/hal-00316447/file/angeo-16-1190-1998.pdf
Description
Summary:International audience Since the middle of 1995, an HF Doppler sounder has been running almost continuously in northern Norway, with the receiver at Ramfjordmoen and the transmitter at Seljelvnes. Concurrent operation of the EISCAT UHF radar in common programme (CP-1) mode has made it possible to study the ionospheric signature of a magnetospheric ULF wave. These are the first results of such wave signatures observed simultaneously in both instruments. It has been demonstrated that the observed Doppler signature was mainly due to the vertical bulk motion of the ionosphere caused by the electric field perturbation of the ULF wave and the first direct observational confirmation of a numerical simulation has been achieved. The wave, which was Alfvénic in nature, was detected by the instruments 8° equatorward of the broad resonance region. The implications for the deduced wave modes in the ionosphere and the mechanism producing the HF Doppler variations are discussed.