FIGURE F.1 The components of the tokamak confinement configuration, one of the more advanced plasma confinement concepts. It uses a strong toroidal field created by external field coils (top left) to stabilize the plasma while using a poloidal field created by a toroidal plasma current to confine the particles (upper right). The final configuration depends on the interaction of these fields (bottom left) and includes a large vacuum vessel to isolate the hot plasma from the surrounding environment (bottom right; people shown for scale). Courtesy of General Atomics and Princeton Plasma Physics Laboratory.