Whistler mode waves observed by MGF search coil magnetometer—Polarization and wave normal features of upstream waves near the bow‐shock

Whistler mode waves observed in the upstream region very close to the bow‐shock is focused from the initial survey for magnetic fed data in a frequency range between 1Hz and 50Hz observed by the search coil magnetometer on board the Geotail satellite. Based on the three component wave form data polarization and wave‐normal characteristics of foreshock waves is first shown as dynamic spectra for the whole Fourier components of the 50Hz band width. Intense whistler mode waves generated in the foot region of the bow‐shock are found strongly controlled in the observed polarization dependent on the angle between directions of the wave propagation and the solar wind flow but no much dependent on frequency. Our simple scheme to derive the wave characteristics which is effective to survey large amount of data continuously growing is also introduced.