Statistics of occurrence of hydromagnetic oscillations in the Pc5 range observed by the STARE auroral radar |
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| Authors: | ADM Walker RA Greenwald |
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| Institution: | Department of Physics, University of Natal, Durban, 4001 S.Central African Republic;Max-Planck-Institut für Aeronomie, Lindau, W. Germany |
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| Abstract: | Quick-look Range-Time-Intensity data from the STARE radar are used to study the diurnal behaviour of hydromagnetic oscillations in the ionosphere. These are known to be associated with Pc5 geomagnetic activity seen on the ground. It is found that the diurnal behaviour at moderate magnetic activities is consistent with a driving mechanism involving the solar wind setting the magnetopause into oscillation through the Kelvin-Helmholtz instability. At highest magnetic activities the picture is less clear and other mechanisms may also be possible. It is also established that the sensitivity of the station to such events depend on the time of day. This is probably because the angle between the radar beam and the line on which resonance occurs varies diurnally, as does the angle between the radar beam and the major axis of the polarization ellipse. |
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