Perfect Conductors

Perfect conductors are used in Maxwell to approximate the following:

• Magnetic field effects at a conductor surface when current flow is restricted to the conductor surface. This condition can exist in conductors with very high conductivity.
• The magnetic field at the surface of a conductor carrying high frequency current, modeled in the eddy current solver when the frequency is very high. Perfect conductors are used in conjunction with Impedance Boundaries in the Eddy Current solvers to handle the following conditions:

• The skin depth in the conductor is less than two orders of magnitude smaller than the dimensions of the structure. In models like this, the mesher may not be able to create a fine enough mesh in the conductor to compute eddy currents.
• The magnetic field decays much more rapidly inside the conductor in the direction that’s normal to the surface than it does in directions that are tangential to the surface.
• The AC current source is relatively far away from the surface where eddy currents occur, compared to the size of the skin depth.

• Conductors in the Electrostatic solver where the voltage is constant in the conductor and there is no electric field penetration in the conductor.
• In the DC Conduction solver where a material contains a high conductivity.
• In conjunction with boundaries requiring the material on one side of the boundary to be the background region such as impedance or resistance boundaries.

Because of the special treatment of perfect conductors, no field solution is performed in these objects, saving time and computer resources when the approximation does not significantly change the field solution outside the conductor.

In order to define an object as a perfect conductor, do one of the following:

• Assign the Perfect Conductor material to the object in the Material Manager.
• Set the object to have a material with a conductivity greater than the conductivity defined in the Material Threshold section of the Design Settings dialog.