The transmission of upstream waves to the magnetosphere from middle to high latitude

Compressional magnetohydrodynamic waves detected in the magnetosphere and at ground stations in the Pc3-4 frequency range (f≈10-50 mHz) are generally believed to be generated upstream of the Earth's bow-shock in reflected proton beams and are conventionally considered to be a dayside phenomenon. An analysis of case events reveals that such wave activity is simultaneously detected at very high latitudes in Antarctica (both in the morning and midnight sector) as well as at low and middle latitude in the northern hemisphere in the dayside sector. It reveals that the observed ground activity was ubiquitously determined, by the same upstream activity, even on field lines stretched into the geomagnetic tail. The transferred wave energy is typically ≈5-10% of the external energy, and it increases with latitude. The local occurrence field line resonance has been investigated, by an analysis of the signal amplitude, phase and polarization aspects. Transmission time from the foreshock to ground has been speculated.