FIRST tokamak in progress*

A conceptual design of FIRST (Formosa Integrated Research Spherical Tokamak)  is in progress. The scientific goals of the device are to perform research on (1) high β plasmas, (2) high bootstrap current density fraction (preferably 100%) operation, (3) the possibility of improved neoclassical ion confinement and the possibility of suppressed turbulent fluctuations, and (4) the maneuverability of particle transport. Here, β is the ratio of the plasma  pressure to the magnetic field pressure. These goals are consistent with the desirable features of tokamak fusion energy reactors, i.e., configurations with good plasma confinement but with ash  removability without sacrificing plasma β and without the need of the non-inductive external current drive for steady state operations. Thus, a tokamak can be an intrinsically steady state plasma confinement concept when its collisioonality parameter ν_* < 1. Here, ν_*  is the ratio of the effective collision frequency to the bounce frequency of the trapped particles. To achieve high β plasmas but with acceptable economic consequences, the device will be a low aspect ratio tokamak. The targeted aspect ratio is in the vicinity of 1.5. The magnetic field will be in the range of 0.1T to 0.5T (or higher when it is upgraded). Plasma minor radius is 30cm and elongation is 2.5 with a positive triangularity parameter. The  stability property, and the β limit of the equilibrium with a high bootstrap current density fraction of the design together with the relevant physics, and the future plan will be reported.