Nuclear fusion device

Object: To compensate, by the provision of flux adjustment windings, for disturbance of magnetic flux in the toroidal direction produced by a toroidal coil due to magnetization resulting at the time of welding a vacuum vessel having welds extending perpendicular to the toroidal direction. Structure: A vacuum vessel having a plurality of welds extending in the direction normal to the toroidal direction is provided with flux adjustment windings each between adjacent welds. Current is passed through the flux adjustment windings in the direction opposite to the direction of current flowing through the toroidal coil. Thus, magnetic field flux based on the magnetization of the welds in the vacuum vessel produced in the welding operation is cancelled by the flux produced by the current flowing through the flux adjustment windings, so that no disturbance of magnetic field flux is produced in the flux produced by the toroidal coil in the toroidal direction. (Moriyama, K.)