Magnets for the tandem mirror fusion power reactor WITAMIR-I

The design of the magnet system for the Tandem Mirror Fusion Power Reactor WITAMIR-I is presented. The central cell of this reactor consists of 34 dc solenoid magnets with a diameter of about 8 m, spaced over a length of 165 m; the central cell magnetic field is 3.6 T. The design of these magnets is relatively simple. The requirements of the end plug magnets are more stringent. In our concept each end plug consists of one barrier mirror solenoid coil, of 3.4 m inner diameter, producing an on axis field of 14 T, two transition coils and a yin-yang pair with a maximum plug field of 6 T and a plug mirror ratio of 1.5. NbTi can be used for all coils except the high field plug solenoid for which Nb3Sn is needed.