Surface Current Density
The Surface Current Density boundary condition
specifies a surface current density at both exterior and interior boundaries. The current density is specified as a three-dimensional vector, but because it needs to flow along the boundary surface, COMSOL Multiphysics projects it onto the boundary surface and neglects its normal component. This makes it easier to specify the current density and avoids unexpected results when a current density with a component normal to the surface is given.
Surface Current Density
When Number of directions is set to Unidirectional, in the Wave Vectors section for The Electromagnetic Waves, Beam Envelopes Interface, enter values or expressions for the components of the Surface current density Js0 (SI unit: A/m). When Number of directions is set to Bidirectional, enter values or expressions for the components of the Surface current density, first wave Js01 (SI unit: A/m) and the Surface current density, second wave Js02.