Engineering evolution of the ignitor machine

Ignitor is the first ignition experiment conceived and designed on the basis of existing technologies and knowledge of plasma physics. Recent design activities within the Ignitor program have led to improve several of the main machine components. The present design of the central post allows for assembling and disassembling of the central transformer coils. The central post can take up the repulsive forces between the coils, this allows for greater freedom in programming the currents in the central coils and flexibility in controlling the plasma shape, the Plasma Chamber (PC) is supported through the ports by the Toroidal Field (TF) magnet structure. The new supports are designed to withstand the electromagnetic forces due to plasma disruptions and to allow the appropriate thermal expansions. The entire machine is cooled by helium gas down to 30 K, a system preferred to the hybrid helium–nitrogen cooling concept. Cooling the structural components at this temperature improves the role of wedging in withstanding the electromagnetic forces on the toroidal magnet. A metallic cryostat under vacuum was adopted. The vacuum reduces temperature gradients in the space immediately surrounding the machine, provides good thermal insulation, and second containment system for tritium.