  In the present paper we study impact of the photospheric 5-minute
oscillations on the ion cyclotron waves in the solar wind. We proceed from the
assumption that the ion cyclotron waves in solar wind are experiencing
modulation with a characteristic period of 5 minutes under the influence of
Alfven waves driven by photospheric motions. The theory presented in our paper
predicts a deep frequency modulation of the ion cyclotron waves. The frequency
modulation is expected mainly from variations in orientation of the IMF lines.
In turn, the variations in orientation are caused by the Alfven waves,
propagating from the Sun. To test the theoretical predictions we have analyzed
records of the ultra-low-frequency (ULF) geoelectromagnetic waves in order to
find the permanent quasi-monochromatic oscillations of natural origin in the
Pc1-2 frequency band (0.1-5 Hz), the carrier frequency of which varies with
time in a wide range. As a result we found the so-called "serpentine emission"
(SE), which was observed in Antarctic at the Vostok station near the South
Geomagnetic Pole. The permanency, range of frequencies, and the deep frequency
modulation of SE correspond to the qualitative properties of ion cyclotron
waves in the solar wind. Clearly expressed 5-minute modulation of the carrier
frequency is particularly important feature of the SE in the context of this
work. We believe that we have found non-trivial manifestation of the solar
5-min oscillations on the Earth.
