Type:2-Tensor, or section
Range:[v_1, …, v_9]

This parameter specifies the relative electric permeability (the coupling between magnetic flux \VField{B} field and the electric field \VField{E}) \tilde{\TField{\mu}}_{\mathrm{rel}} as follows:

\tilde{\TField{\mu}} &= \tilde{\TField{\mu}}_{\mathrm{rel}} \sqrt{\varepsilon_0\mu_0}


Usually the relative electric permeability \tilde{\TField{\mu}}_{\mathrm{rel}} is defined relative to the background permittivity and permeability. We do not follow this convention as it is not clear how this convention is applied for general an-isotropic tensors \TField{\varepsilon} and \TField{\mu}.

The relative electric permeability \tilde{\TField{\mu}}_{\mathrm{rel}} is typically linked to the magnetic permittivity \tilde{\varepsilon}. See there for detailed discussion of bi-anistropic materials.