Search coil

The search coil magnetometer, based on an Inductive Sensor (also known as Inductive loop and inductive coil), is a magnetometer which measures the varying magnetic flux thanks to Lenz's law. An inductive sensor associated to a conditioning electronic constitute the search coil magnetometer (also known as induction magnetometer). It is a vector magnetometer which can measure one or more components of the magnetic field. A classical configuration uses three orthogonal inductive sensors. The search-coil magnetometer can measure magnetic field from mHz up to hundreds of MHz.

The inductive sensor is based on Faraday's law of induction. The temporal variation of the Magnetic Flux ${\displaystyle \Phi }$ through a N turns circuit will induce a voltage ${\displaystyle e}$ which follows:

which can be expressed in a simpler way:

by assuming that the induced magnetic field B is homogeneous over a section S (the Magnetic flux will be expressed ${\displaystyle \Phi =B\times S}$).

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