Experimental Modeling on the Recyclable Magnetically Insulated Transporting Lines Aimed at the IFE Reactor

A series of experiments has been carried out on the S-300 pulsed power machine, devoted to the study of a section of magnetically insulated vacuum transporting line (MITL). The length of MITL section was 1 cm, the current flow density up to 700 MA/cm² by the linear current flow density being up to 7 MA/cm. These parameters fairly correspond to those of the Sandia Laboratories conceptual project of IFE reactor based on the fast Z-pinch. The goal of experiments was to study of the near-electrode plasma dynamics and its effect on the energy transfer. In most experiments, input and output current temporal behavior coincides up to some point (in our conditions, with a Ni cathode, up to 220-260 ns after the current start) corresponding to the gap fill by the relatively rare weakly-luminescent plasma, which front reconnects the gap with the maximal transverse velocity observed ~2.5times10⁷ cm/s. At the moment of its coming, the output current becomes reduced, compared to the input current. The dynamics of both dense brightly luminescent plasma and rare plasma corona has been investigated. Absolute measurements of the HXR Bremsstrahlung show that even at the point of maximal electron current leaks, it did not exceed some dozen of kA. Such leaks cannot give any essential input into the current balance. Effect of impurities absorbed by the solid electrodes has been studied, as well as the influence of different electrode materials (Ni, Pb, Al, Au). In particular, in the case of golden or lead cathode, the insulation time was extended up to 400 ns. With respect to the whole project, our conclusion is quite optimistic, to wit, we have found the idea of recyclable transporting lines being adequate to the IFE reactor requirements.