The Boundary Current Source node adds a current source Qj on the boundary.

It is applicable to interior boundaries that represent either a source or a sink of current. Add a contribution as a Harmonic Perturbation by right-clicking the parent node or click Harmonic Perturbation in the Physics toolbar. For more information see Harmonic Perturbation — Exclusive and Contributing Nodes in the COMSOL Multiphysics Reference Manual.

Enter a value or expression for the Boundary current source Qj (SI unit: A/m2). The default is 0 A/m2.