[en] The primary emphasis has been to examine the feasibility of a homopolar machine as an energy transfer and storage element in the circuit of the TNS doublet, to address the related switching problems, and to consider the nature of the plasma showdown at the end of the burn cycle. Parameters supplied for the studies set the peak current and voltage at about 3 MA and 1 kV, respectively, with a 2-s start-up for the ohmic-heating phase. The stored energy in the ohmic-heating coils was estimated to be 500 MJ and the total flux change to be 34 Vs. Of this amount, 20 Vs supplies the plasma inductive loading and 8 Vs the plasma resistive losses. The remainder powers the burn phase. The six parts of the study analyze the circuit, present a minimal conceptual engineering analysis of an air core superconducting field coil excited homopolar machine, provide a comparative design of an iron dominated homopolar machine, address the circuit or current interruption problem as well as the connecting bus, and discuss the plasma shutdown. Approximate costs are developed for both homopolar machines. In particular, a variable capacitance homopolar machine with superconducting field coils has been considered