- Researchers have traced a very significant increase in special continuous oscillations with pearl-type structures called Geomagnetic Pc1 pearl oscillations on the surface of the Earth in the recovery phase of geomagnetic storms.
- This study is significant for investigating of precipitation particles during geomagnetic storms and can help us understand the radiation hazard to satellites and astronauts.
- Earth’s magnetic field forms a protective shield around us, and various plasma waves are generated in this magnetic field cavity.
- Geomagnetic storms often cause a dent in this protection.
- Energetic particles are either accelerated or lost from the Earth’s radiation belts during these storms.
- This is responsible for changes in plasma environment leading to growth of low-frequency waves called Electromagnetic ion-cyclotron (EMIC) wave instability which is seen as the magnetic field oscillations (0.1-5 Hz) called as Pc1 pulsations.
About the Geomagnetic Pc1 pearl oscillations:
- The Geomagnetic Pc1 pearl oscillations are amplitude-modulated structured narrow-band signals, which 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.
Findings of the study:
- A clear increase in the number of Pc1 at night was observed compared to the day.
- This is because the attenuation of Pc1 waves upon propagation via the ionospheric waveguide towards lower latitudes is weaker during night hours.
- Similarly, 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.
SOURCE: THE HINDU, THE ECONOMIC TIMES, PIB