Conceptual design of SST-1 tokamak

The superconducting steady-state tokamak (SST) will have major and minor radii, Ro and a, of 1.05 m and 0.20 m respectively. The maximum toroidal field will be 2.9 T at Ro and plasma current Ip ∼ 220 kA. The D-shaped plasma, in a double-null (DN) divertor configuration, will have κx lying in the range 1.7--2.0 and δx ≅ 0.4--0.7, corresponding to q95 in the range 5--7. At flattop, βp and ell i would lie in the ranges 0.7--1.4 and 0.6--1.2 respectively. The TF and PF coils will be superconducting (NbTi), while the ohmic transformer and correction coil system will be made of copper. Steady-state current drive, and also part of the current rampup, will be based on lower hybrid current drive (LHCD). ICRF and NBI will provide auxiliary heating. Fast vertical control will make use of saddle coils placed inside the vacuum vessel, while the PF coils will be used for shape control. The outer divertor will have a slot configuration to permit operation with high recycling and impurity injection. The TF and PF systems and vacuum vessel are designed to allow later upgradation to a high-current, larger plasma with Ip = 400 kA, a = 0.29 m, Ro = 1.16 m, with lower elongations