Geomagnetic pearl oscillations increase in the recovery phase of geomagnetic storms

Source: The post is based on the article “Geomagnetic pearl oscillations increase in the recovery phase of geomagnetic storms” published in PIB on 2nd May 2023

What is the News?

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. 

What are Geomagnetic Storms?

A geomagnetic storm is a major disturbance of Earth’s magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth. 

These storms result from variations in the solar wind that produce major changes in the currents, plasmas and fields in Earth’s magnetosphere.

How do Geomagnetic Storms impact Earth’s magnetic field?

Earth’s magnetic field forms a protective shield around us, and various plasma waves are generated in this magnetic field cavity. However, 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 the plasma environment leading to the 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.

What are Pc1 pearl oscillations?

The Geomagnetic Pc1 pearl oscillations are amplitude-modulated structured narrowband 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.

Evidence of these pulsations are abundant in the mid and high-latitude regions. However, at very low latitude stations, it is not frequent.