The Harmonic Perturbation subnode (it is of the exclusive type) is available from the context menu (right-click the parent node) or in the
Physics toolbar, click the
Attributes menu and select
Harmonic Perturbation. For more information see
Harmonic Perturbation — Exclusive and Contributing Nodes in the
COMSOL Multiphysics Reference Manual.
Enter the value or expression for the components of the Electric field E0 (SI unit: V/m). The defaults are 0 V/m.