Analogy to the transformer: primary and secondary coils, connected by an iron core

The 'secondary coil' consists here of a plasma that is magnetically confined in a toroidal (circular) vessel and carries the induced current. The plasma is stabilized by a twisted magnetic field configuration generated by additional coils.

The transformer induces a pulsed current that heats up the plasma at each discharge, but the 'flame' is extinguished again then.

Both for reaching reactor-like conditions and for stationary operation - which is possible for this type of construction as well - additional heating is required.