Experimental studies of field-reversed configuration translation

In the FRX-C/T experiment [Proceedings of the 9th Symposium for Engineering Problems of Fusion Research (IEEE, New York, 1981), p. 1751], field-reversed configuration (FRC) plasmas have been formed in, and launched from, a field-reversed theta-pinch source and subsequently trapped in an adjacent confinement region. No destructive instabilities or enhanced losses of poloidal flux, particles, or thermal energy are observed for FRC total trajectories of up to 16 m. The observed translation dynamics agree with two-dimensional magnetohydrodynamic (MHD) simulations. When translated into reduced external magnetic fields, FRC’s are observed to accelerate, expand, and cool in partial agreement with adiabatic theory. The plasmas reflect from an external mirror and after each reflection, the axial kinetic energy is reduced by approximately 50%. Because of this reduction, FRC’s are readily trapped without the need of pulsed gate magnet coils.