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(GIST OF YOJANA) Geomagnetism: Applications

[October-2021]

Geomagnetism: Applications

The magnetic field, since it originates inside the earth and travels through its different constituents and materials, turns into a handy tool to peer inside and examine it. Some of the material attracts electromagnetic waves towards it and some resist. The delineation of electromagnetically conductive and resistive bodies can help earmark sources of natural hazards or natural resources.

The antiquity of the Indian Institute of Geomagnetism (IIG) goes back to almost two centuries and it is a force to reckon within the field of geomagnetism and allied research areas. It has earned a great reputation of being one of the best in the world, with consistency in innovating new and advanced research. It is a global leader in magnetic and electromagnetic data collection.

This data is eagerly sought by pioneers from around the world for their geomagnetic research. Geomagnetism is a global phenomenon and hence it cannot be understood in isolation or locally.

Research areas:

The research areas that are covered by IIG encompass a wide spectrum- on one hand, it explores the interior of the earth, and on the other, its vast boundaries reach the sun to understand its dynamics. If it explores different layers of the earth, it also investigates a gamut of atmospheric strata. If it uses seismic waves to unravel the earth’s properties, it also harnesses radio waves to ensure seamless communication. Out of the sun, earth, or the dark space between these two entities, none have been left unexplored by IIG.

Magnetic minerals:

The magnetic minerals embedded in crustal rocks are harnessed to map Curie temperature symptomatic of the crust-mantle magnetic transition zone. They are also used to understand the regional deformities and structural framework of the continental and oceanic realm.

The mineralised zones and geotectonic fault categorisation become easier with remotely sensed magnetic data. The composite magnetic anomaly map developed at IIG is in a league of its own. The experts in the field can mine a wealth of information regarding the regional geology (natural resources) and tectonic framework of India (faults, lineaments, weak planes).

Magnetic minerals play a very important role in understanding climate changes and environmental fluctuations. These minerals are quite stable in the unchanging physico-chemical domain but are quite sensitive to the changes in those circumstances.

They alter themselves to maintain equilibrium with the surrounding. Laboratory investigations reveal the degree and phase change in magnetic mineralogy, which can then be associated with a climatic or environmental process.

The solar magnetism impacts celestial entities which include earth as well. The energetic particles emanating from the sun influence earth’s magnetosphere, ionosphere, mesosphere, and thermosphere. Solar flares, coronal mass ejections, high-speed solar wind, and solar energetic particles are the manifestation of dynamic flux.

The earth is also magnetic and the genesis of this field is theorised, modelled, and simulated to be at the core-mantle boundary. The field lines traverse through different earth layers to protectively blanket our planet.

Conclusion:

The atmospheric tides are global scale variations in wind, temperature, and pressure, tied to solar input. They occur throughout the atmosphere on a regular basis and are seen once or twice daily (diurnally and semidiurnal), with smaller tides at more frequent intervals.

The tides move westward with the sun, driven by solar radiation, its absorption, and re-emission at various heights. These processes are active even when the sun is ‘inactive’ or quiet. But there is a crescendo of events when there is a solar ‘storm’.

The cataclysmic burst of charged particles and radiation completely rearranges global thermospheric circulation in a matter of hours. The ionosphere and magnetosphere are a closely-coupled system