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Why must the fluid in Earth’s outer core conduct electricity for the dynamo to work?

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geomagnetic field The magnetic field of a bar magnet has a simple configuration known as a dipole field. Close to Earth's surface this field is a reasonable approximation of the actual field.

The fluid in Earth’s outer core must be electrically conducting for the geomagnetic dynamo to function because the mechanism relies on the movement of material to generate an electric current.12

In this process, the motion of the liquid iron core carries conducting material across an existing magnetic field, which induces an electric current. This current then generates its own magnetic field, which interacts with the fluid motion to create a secondary magnetic field, effectively amplifying and sustaining the planet's overall magnetic field.12

Furthermore, because the fluid is a conductor, magnetic field lines are essentially "frozen" into the material, forcing them to move as the fluid moves. This allows the fluid's convective and rotational motions to twist and distort the field lines, a critical step in the self-sustaining cycle of the dynamo. Without electrical conductivity, these currents could not be generated or maintained, and the magnetic field would dissipate.1