PRODUCTION OF A LONG LIFE FRC PLASMA BY TRANSLATION, AND THE STUDY OF ITS CONFINEMENT PROPERTIES

摘要

A conceptual design of a neutron lean D-~3He fuelled FRC fusion reactor is presented. In this design, a 0 pinch produced FRC plasma is assumed to be translated from a formation region to a confinement and heating region. In the FRC Injection Experiment (FIX) machine, a θ pinch produced FRC plasma with T(= T_e + T_i) ≈ 400 eV and n ≈ 6 × 10~(21) m~(-3) is translated into a large bore (r = 0.4 m) metal vessel. Though the density is decreased by two orders of magnitude, the decrease in temperature is smaller than predicted by the adiabatic theory. In addition, when the FRC is reflected at the mirror field, plasma heating occurs owing to the thermalization of the translational kinetic energy. This rethermalization is observed only when the translational velocity exceeds the sound velocity in the plasma, signifying the intervention of some shock mechanism. As a result of this translation, a configuration lifetime of about 0.5 ms is attained. In this FRC plasma, a magnetic field fluctuation localized near the separatrix is detected. High β sheath thickness measurement shows that the plasma that has escaped out of the configuration is flowing along the magnetic lines of force outside the separatrix.