AC/DC Module Physics Interface Guide
The interfaces in the AC/DC Module form a complete set of simulation tools for electromagnetic field simulations. To select the right physics interface for describing the real-life physics, the geometric properties and the time variations of the fields need to be considered. The interfaces solve for these physical quantities — the electric scalar potential V, the magnetic vector potential A, and the magnetic scalar potential Vm.
Each physics interface has a tag which is of special importance when performing multiphysics simulations. This tag helps distinguish between physics interfaces and the variables defined by the physics interface have an underscore plus the physics interface tag appended to their names.
The Model Wizard is an easy way to select the physics interface and study type when creating a model for the first time, and physics interfaces can be added to an existing model at any time. Full instructions for selecting interfaces and setting up a model are in the COMSOL Multiphysics Reference Manual.
In 2D, in-plane and out-of-plane variants are available for problems with a planar symmetry as well as axisymmetric interfaces for problems with a cylindrical symmetry. See What Problems Can You Solve? and Table 1-1 for information about the available study types and variables. See also Overview of the User’s Guide for links to the chapters in this guide.
When using an axisymmetric physics interface it is important that the horizontal axis represents the r direction and the vertical axis the z direction, and that the geometry in the right half plane (that is, for positive r only) must be created.
In the COMSOL Multiphysics Reference Manual:
 
AC/DC
stationary; stationary source sweep; frequency domain; time dependent; small signal analysis, frequency domain; eigenfrequency
stationary; frequency domain; time dependent; eigenfrequency
stationary; frequency domain; time dependent; eigenfrequency
stationary; frequency domain; time dependent; small signal analysis, frequency domain; eigenfrequency
stationary; time dependent; stationary source sweep; eigenfrequency; frequency domain; small signal analysis, frequency domain; eigenfrequency
stationary; stationary source sweep; frequency domain; small signal analysis, frequency domain
3D, 2D, 2D axisymmetric
stationary; frequency domain; time dependent; small signal analysis, frequency domain; coil geometry analysis (3D only); time to frequency losses; eigenfrequency
Heat Transfer
Electromagnetic Heating
stationary; time dependent; frequency-transient; small-signal analysis; frequency domain; frequency-stationary; frequency-stationary, one-way electromagnetic heating; frequency-transient, one-way electromagnetic heating
1 This physics interface is included with the core COMSOL package but has added functionality for this module.
2 This physics interface is a predefined multiphysics coupling that automatically adds all the physics interfaces and coupling features required.