Stabilization of the field-reversed configuration (FRC) tilt instability with energetic ion beams

The stabilization of the internal tilt mode of a field-reversed configuration by injecting a minority energetic ion component has been investigated numerically. Calculations that follow ion orbits in a specified three-dimensional magnetic field configuration, corresponding to a partially tilted field-reversed configuration, demonstrate how a beam can provide a restoring force to the n=1 tilt instability. A fully self-consistent three-dimensional numerical model, which treats the background plasma as a Hall fluid and the energetic ions as a collisionless Vlasov species, has also been developed. Calculations have been made for a variety of beam injection parameters, and indicate that the tilt mode can be stabilized with a beam energy of about 40% of the total, beam plus plasma, energy.