Theory of ion dynamics and heating by magnetic pumping in FRC plasma

Abstract

A new mathematical framework is developed for efficient evaluation of ion heating during magnetic pumping of field-reversed configuration (FRC) plasmas. The topology of ion trajectories is examined through the use of action variables applied to a typical FRC equilibrium. Orbit bifurcations are identified and characterized analytically. These bifurcations are associated with the breakdown of the action variables as adiabatic invariants. The associated pitch-angle-mixing is important to the efficiency of magnetic pumping and is included in a new model for the kinetic behavior of the ions during the heating process.