Recent advances in the SPIRIT (Self-organized Plasma with Induction, Reconnection, and Injection Techniques) concept

Since its inception at the 1997 Innovative Confinement Concept meeting, the Self-organized Plasma with Induction, Reconnection, and Injection Techniques (SPIRIT) concept has been continuously advanced both theoretically and experimentally. The main features of this concept are: (1) formation of large-flux Field Reversed Configuration (FRC) plasmas by merging two spheromaks with opposite helicities; (2) flexibility to assess FRC stability by varying the plasma shape and kinetic parameter, by using passive stabilizers, and by injecting energetic ions; (3) sustainment of the FRC for a time significantly longer than the energy confinement time using an ohmic transformer and/or neutral beam injection. Experiments carried out in TS-3/4 and SSX and more recently in Magnetic Reconnection Experiment (MRX) have further verified the effectiveness of this formation scheme for large-flux FRCs. An improved understanding of FRC stability over plasma shape and kinetic parameter has been obtained in MRX. New numerical simulations showed that FRC plasmas can be globally stabilized by injecting energetic ions. Many of these aspects of the SPIRIT concept can be further studied in the current MRX device.