Antisymmetric RMF current drive in FRCs

A major concern for Rotating Magnetic Field (RMF) current drive of an FRC is that a transverse magnetic field tends to open the field lines, thus compromising confinement. In recent FRC current drive experiments it was found that thermal confinement is much improved when an antisymmetric RMF is applied, rather than the usual symmetric RMF. A field line tracking analysis showed that with a combination of partial penetration and antisymmetric RMF, the field lines remain closed for larger ratios of B (omega)/B (e) than was previously thought. In this paper the analysis is extended to more fully understand the boundaries of when and where the field lines are expected to remain closed when antisymmetric RMF current drive is applied to an FRC.