The Geomagnetic Pc1 pearl oscillations are amplitude-modulated structured narrow-band signals.
They are signatures of low-frequency EMIC waves generated by resonant wave-particle interactions in the Earth’s magnetosphere.
The observation of these oscillations is a proxy for the measurement of particle precipitation in the Earth’s magnetosphere.
Evidences of these pulsations are abundant in the mid and high-latitude regions.
At very low latitude stations, it is not frequent.
These waves are an important component of space weather in the near-Earth environment.
During the solar maximum period, the transmission rate of Pc1 waves to the equator was diminished than during the solar minimum.
The annual and seasonal patterns of Pc1 occurrence showed an inverse relation with sunspot numbers at both stations.
An association of these pulsations with active geomagnetic conditions showed the occurrence of Pc1 increasing significantly in the recovery phase of geomagnetic storms.