Axial compression of an FRC plasma

A new concept for plasma heating using axial magnetic compression of a field-reversed configuration (FRC) plasma is proposed. In this concept, the FRC plasma is compressed only axially, keeping the magnetic flux between the separatrix and the confining chamber (flux conserver) wall unchanged, while allowing the plasma to expand radially. A simple model based on an empirical scaling law of FRC confinement and on the assumption that the compression is done adiabatically, predicts that in addition to heating the plasma, confinement improvement will also be accomplished with this concept. This compression will be done by energizing segmented mirror coils successively in such a way to decrease the length of the confinement region between mirror coils. The apparatus for this axial compression was developed and an experiment was carried out. In this experiment the plasma was compressed by about 30% and the plasma life time of about 500μs was increased by about 50μs. (author)