TJ-II:Vacuum system

Vacuum vessel

The all-metal TJ-II vacuum vessel has a helical geometry and has 96 ports. The vacuum vessel is made of non-magnetic steel (304 LN) with a thickness of 10 mm. The CC/HX coil is outside of the vacuum vessel thanks to a helical groove built into the vessel. This groove has a wall thickness of 7 mm for clearance reasons. The groove is protected along the entire toroidal circumference against damage due to the bean-shaped plasma by 3 mm stainless steel sheets for low and medium power operation and graphite tiles for high power operation. Furthermore, the vacuum vessel is protected on the areas where the neutral beams deposit a residual shine-through heat flux.

Vacuum system

The vacuum vessel is pumped through four symmetrically spaced bottom ports to a base pressure of 10^-8 mbar. Four identical and independent vacuum pumping subsystems are used. ^[1] ^[2]

References

[1] J. Botija et al, Vacuum vessel, wall protection, pumping system and poloidal limiters of the Spanish stellarator TJ-II, 15^th IEEE/NPSS Symposium on Fusion Engineering 1 (1993) 529-532

[2] F. Tabarés, The vacuum system of the TJ-II stellarator, Vacuum 45, Issues 10-11 (1994) 1059-1061

[1]

[2]