The Magnetic Particle–Field Interaction multiphysics coupling () computes the current density due to the motion of charged particles and assigns the current density components to a set of dependent variables that are defined on the domain mesh elements that contain the particles. It also applies the accumulated current density as a source when computing the magnetic vector potential.

The computation of the current density is controlled by the Particle release specification list in the settings window for the Charged Particle Tracing interface. If Specify release times is selected, each particle contributes to the current density based on its instantaneous location. If Specify current is selected, each model particle is treated as representing a number of charged particles per unit time, leaving behind a contribution to the current density in mesh elements it has previously passed through.

The Label is the default multiphysics coupling name.

The Name is used primarily as a scope prefix for variables defined by the coupling node. Refer to such variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different coupling nodes or physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.

The default Name (for the first multiphysics coupling in the model) is mpfi1.

This section defines the physics involved in the multiphysics coupling. By default, the applicable physics interface is selected in the Source and Destination lists.

You can also select None from either list to uncouple the node from a physics interface. If the physics interface is removed from the Model Builder then the applicable list defaults to None as there is nothing to couple to.