The Particle Field Interaction, Non-Relativistic Interface combines charged particle tracing with electrostatics to model nonrelativistic beams of charged particles that can create significant space charge density distributions in the domains that contain the particles. The space charge density may, in turn, exert a significant electric force on the particles, resulting in a bidirectional coupling between the particle trajectories and the electric potential.

An iterative solver loop that consists of a time-dependent solver for computing particle trajectories and a stationary solver for computing all other dependent variables can be set up automatically using the Bidirectionally Coupled Particle Tracing study step, described in the COMSOL Multiphysics Reference Manual.