It is now a common knowledge that Earth’s magnetic field is similar to that produced by a simple bar magnet. This means that Earth’s magnetic field has the structure of a dipole field. Do you know that the axis of the magnetic field is inclined by about 10 degrees to the rotation axis of the Earth? Its magnetic field intensity is about 30,000 to 60,000 nano Tesla (nT) at the earth surface. This intensity decreases as the inverse cube of the distance (1/R^3) from the earth. The internal field of the earth appears to be generated in the earth’s core by a dynamo process associated with the circulation of liquid metal in the core and driven by convective heat effect.
