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CLUSTER SATELLITE OBSERVATIONS OF FIELD LINE RESONANCES IN THE DAYSIDE MAGNETOSPHERE. P. T. I. Eriksson , L. G. Blomberg. Alfvén Laboratory, Royal Institute of Technology, Stockholm, Sweden. Background. Assume wave propagation on the form.
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CLUSTER SATELLITE OBSERVATIONS OF FIELDLINE RESONANCES IN THE DAYSIDEMAGNETOSPHERE P. T. I. Eriksson, L. G. Blomberg Alfvén Laboratory, Royal Institute of Technology, Stockholm, Sweden
Background Assume wave propagation on the form The hydrodynamic equations in a cylindrical geometry then gives Toroidal and poloidal mode resp. Two limit cases: In general (finite m) the two modes are coupled
Background cont. Background
Spacecraft orbit • Plot in GSM-coordinates • Snapshot taken at 16:00 UT
Data bandpass-filtered 2-10 mHz • Background magnetic field defined by • 20 min running average • r~radial; e~eastward; p~parallell
Summary of observations • On 17 August 2002 a FLR event is observed in the dayside magnetosphere. • The oscillations occur at one stable frequency, 4.2 mHz • in the satellite frame. • Radial polarisation of the magnetic field indicates the • poloidal mode.