Thermonuclear device

In a thermonuclear device of reducing ripple magnetic fields in toroidal magnetic fields generated in the torus direction of a torus type vacuum container by means of magnetic bodies, a portion of vacuum walls constituting access ports of the vacuum container is combined with those post portion of the vacuum container. Further, a magnetic body is disposed in a heat insulated vacuum region of the toroidal magnetic field coils surrounded with the vacuum walls. The post portion of the vacuum container is bisected into the torus direction by means of electrical insulators and electrical conduction is secured in the torus direction by means of bellows, to increase the resistance on the side of the vacuum container and cause the plasma current flow efficiently. (H.T.)