4. Materials

4.1 Magnetic materials

The energy stored can be up to 20 times greater in a winding on a magnetic core than in a winding on a non-magnetic material. This energy depends on the induction B.

In fact, all materials subjected to an external magnetic field H can be characterized by the induction B and the field H prevailing at any point of these materials.

In the case of a non-magnetic material, the induction is little different from µ _o H, where µ _o is the vacuum permeability. It is of the order of 0.1 T (for a non-superconducting coil).

In the case of a magnetic material, induction is expressed by the relation :...