Divertor for a steady-state gas-dynamic trap

An analysis is carried out into the possibility of using a device topologically equivalent to a nonparaxial magnetohydrodynamic (MHD) stabilizer as a divertor for the projected ALIANCE source of fusion neutrons based on the gas-dynamic trap, which should operate in a continuous mode. A side effect of adding a divertor to a linear trap is the expected improvement in plasma MHD stability, which was previously observed at the TARA (Casey et al 1988 Phys. Fluids 31 2009-16) and HIEI (Yasaka et al 2001 Fusion Technol. 39 350-3) facilities. To assess the effect of MHD stabilization by a divertor, the article indicates a method for finding stability rings, and also calculates the degree of expansion of the plasma flux in the divertor. The analysis showed that a good divertor, which provides a high degree of expansion, cannot be a good MHD stabilizer, which provides a large margin of stability. The divertor configurations made up of two and three coils are studied, their advantages and disadvantages are described. The final part of the article presents the calculations of the magnetic field in an end cell with a superconducting divertor designed for the GDMT gas-dynamic multi-core trap project (Beklemishev et al 2013 Fusion Sci. Technol. 63 46-51).