Copper shell and toroidal support structure for RFX

The Copper Shell and the Toroidal Support Structure are two new components of the modified RFX machine. The Copper Shell is a thin toroidal shell (3 mm thick, 2m major radius and 0.5m minor radius), whose main function is plasma column passive stabilization during the pulses. The electrical continuity of the shell both along the toroidal and poloidal directions is interrupted by insulated gaps. The poloidal gap is specifically designed in order to minimize the magnetic field errors in the plasma region: it is manufactured inserting a 2mm thick PTFE layer in between the overlapping ends of the shell. The Toroidal Support Structure is a Stainless Steel Shell having maximum thickness 47 mm, major radius 2 m and minor outer radius 0.6 m. Its function is mainly to support the vacuum vessel and copper shell, 48 toroidal field coils, 16 field shaping coils and 192 new saddle coils. The fully machined external surface with precise toroidal and poloidal grooves allows the assembly of all the machine components with the required accuracy. The insulated vertical joints between the quarters of the structure have been specifically designed and fabricated in order to get the electrical and mechanical resistance required during operations.