A multistation study of long period geomagnetic pulsations at cusp and boundary layer latitudes.

摘要: Abstract The characteristics of 1–20 mHz (Pc5) geomagnetic pulsations recorded during the daytime on ground at cusp and boundary layer latitudes have been examined. On quiet moderately disturbed days major spectral contributions are due to three different mechanisms. Sustained oscillations whose properties consistent with Kelvin-Helmholtz instability low latitude dominant mechanism −70 −75 latitude. Transient irregular frequently seen single stations foot polar cap field lines. Occasionally similar transients occur essentially simultaneously widely spaced accompanied by absorption spikes riometer records. latter signals most likely solar wind pressure pulses magnetopause. At contribution arises from sustained centred magnetic noon. Although their occurrence is related proximity cusp's particle signature, it may be more appropriate discuss these in terms fluctuations or mantle currents.