Stability and compressional heating of large field-reversed configurations in the FRX-C/LSM device

Recent data from the FRX-C/LSM device [Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1989), Vol. II, p. 517] concerning the stability, translation, and compression heating of field-reversed configurations (FRC’s) are reported. FRC tilt instabilities are clearly observed for the first time, a major step toward reconciling theory and experiments. Grossly stable FRC’s appear to be restricted to very kinetic and elongated plasmas. Internal probing of translated FRC’s reveals substantial toroidal field and nearly force-free magnetic field profiles in the central region of the compact toroid. High-power magnetic compression of translated FRC’s is demonstrated. Substantial heating is observed, while the FRC confinement properties remain mostly unchanged.