Plasmoid Dipole Rotation in a Theta Pinch

The behavior of the toroidal plasmoid formed in a theta pinch due to trapping of magnetic field lines has been photographed with an ultra‐high‐speed image‐converter camera. Photographs show the plasma ring rotating about an axis perpendicular to the applied magnetic field. This rotation is seen not only as a possible explanation for the sudden disappearance of the trapped magnetic field, but as a mechanism for accelerating the ions caught in the plasmoid. A preliminary analysis provides an upper bound to the ion energies obtainable through such a mechanism.