Chapter 9: Problem 7

Where and how is Earth’s magnetic field generated?

Short Answer

Expert verified

Earth's magnetic field is generated mainly due to the dynamo effect within the Earth's liquid outer core, which consists of electrically conducting molten iron. The movement of this molten iron, driven by convection currents and influenced by Earth's rotation, creates electrical currents within the outer core. These currents produce a magnetic field through a self-sustaining process known as the geomagnetic dynamo, which maintains a stable and protective magnetic shield around the Earth.

Step by step solution

Understanding Earth's Magnetic Field

Earth's magnetic field is a crucial component of our planet, protecting the Earth and its inhabitants from harmful solar radiation. The magnetic field is generated in the Earth's core, a layer composed of molten iron and other elements. This core surrounds the inner solid core of the Earth, containing primarily iron and nickel.

The Role of Earth's Core

The Earth's core plays a crucial role in generating the magnetic field. The outer core consists of electrically conducting liquid iron, which is constantly in motion due to convection currents generated by heat flow from the inner core to the mantle above. As the liquid iron moves, it carries electric charges with it, creating electrical currents within the outer core.

The Dynamo Effect

The generation of Earth's magnetic field is primarily attributed to the dynamo effect. The dynamo effect is a process through which the kinetic energy of the moving liquid iron in the outer core is converted into magnetic energy. This happens due to the interaction between the electric currents and the rotation of the Earth. In the presence of a magnetic field, the movement of electrically charged particles, such as the molten iron in the Earth's outer core, generates a force known as the Lorentz force. This force causes the charged particles to move in a spiral path, resulting in the creation of electric currents within the outer core. These electric currents, in turn, generate a magnetic field.

Self-sustaining Magnetic Field

A crucial aspect of the Earth's magnetic field is that it is self-sustaining. As the existing magnetic field interacts with the electrical currents in the outer core, it generates a new magnetic field. This new magnetic field reinforces the original magnetic field, maintaining a stable and continuous magnetic field around the Earth. This self-sustaining process is known as the geomagnetic dynamo.

In Summary

Earth's magnetic field is generated within the Earth's liquid outer core through a process called the dynamo effect. The movement of electrically charged molten iron in the Earth's outer core, interacting with the existing magnetic field and Earth's rotation, generates electric currents, which in turn produce the magnetic field. This self-sustaining process is essential for maintaining a stable and protective magnetic shield around the Earth.

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Where and how is Earth’s magnetic field generated?

Short Answer

Step by step solution

Understanding Earth's Magnetic Field

The Role of Earth's Core

The Dynamo Effect

Self-sustaining Magnetic Field

In Summary

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