Further Considerations of a Flow- Stabilized Z-Pinch for Megagauss Fusion

The Sheared-Flow Stabilized (SFS) z-pinch [1] offers the possibility of a truly compact fusion reactor due to operation at multi-megagauss magnetic fields. That said, if D-T is used as the fusion fuel, the burden of handling tritium, generated by neutron reactions with lithium in the blanket and also residing in the unburnt portion of the fusion plasma, can still demand very large installations [2] at the power plant. Use of so-called “advanced” fuels, e.g., D-3He and catalyzed D–D, might avoid such burdens and improve the overall economic prospects for fusion power. We consider here the SFS z-pinch in terms of quasi-steady flow through three stages, and obtain some potentially useful scaling relations between plasma dimensions and operating currents. For the “conventional” use of D-T, it appears possible to achieve a scientific breakeven demonstration at megampere currents in pinch column lengths less than a meter. Such currents are well within the capabilities of low-impedance pulsed power systems [3] at multi-megajoule levels. For power reactor operation, higher currents are needed and/or longer pinch lengths. With higher currents and larger dimensions, the use of so-called advanced fuels may be feasible. To achieve this will require further research to establish the necessary control of plasma gun operation to supply the pinch flow, and great precision to obtain the needed sub-millimeter pinch diameters.