The Thin Low Permeability Gap node adds a boundary condition on an internal boundary which allows for a discontinuity in the magnetic scalar potential. This feature represents a thin layer in a magnetic material filled with another material that has smaller relative magnetic permeability. Use this feature to model, for example, an air gap in a magnetic circuit. Enter a relative magnetic permeability μr for the thin layer material as well as a thickness ds. The difference in magnetic flux through this boundary is given by

where Vmu is the magnetic scalar potential on the upside of the boundary selection and

Vmd is the magnetic scalar potential on the downside.

The default Relative permeability μr (dimensionless) uses values From material. For User defined enter a different value or expression. Enter a value or expression for the Surface thickness ds (SI unit: m).