Application of a magnetized coaxial plasma gun for formation of a high-beta field-reversed configuration

We have tested a field-reversed configuration (FRC) formation with a spheromak injection for the first time. In this method, initial pre-ionized plasma is injected as a magnetized spheromak-like plasmoid into the discharge chamber prior to main field reversal. The FRC plasma with an electron density of 1.3 × 1021 m−3, a separatrix radius of 0.04 m and a plasma length of 0.8 m was produced successfully in initial background plasma of about 1.6 × 1019 m−3 by spheromak injection. The density is about one third of the conventional formed by the z-ionized method.