The Preliminary design of SUNIST-2:A Spherical Tokamak

SUNIST-2 is the successor to the SUNIST spherical tokamak (ST), which designed through the cooperation of Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) and Tsinghua University (THU). Its major objective is to explore various startup and heating methods for ST with higher magnetic field. SUNIST-2 boasts a major radius of 0.525 m and a minor radius of 0.325 m,with a toroidal field capable of reaching up to 1 tesla. The vacuum vessel is notably large compared to the size of plasma, featuring an outer diameter of 2.27 m. This additional space is intentionally reserved for the antennas of radio frequency waves. The magnet system of SUNIST-2 comprises Toroidal Field Coil (TF), a Central Solenoid coil (CS), Poloidal Field coil (PF), Merging Compression Coils (MC), Diverter Figuration Coils (DF) and Compensation Coils (CC), all coils are crafted by cooper. Currently, both the concept design and engineering design of SUNIST-2 have been completed, and the manufacturing of the vacuum vessel and the coils have been finalized. In this paper, the key engineering features and design aspects of SUNIST, including electromagnetic parameters of SUNIST-2 are presented.