A plasma gun has been developed which projects ionized matter (metallic and deuterium ions) at speeds up to 2×${10}^7$ cm per second. There is some evidence to support the hypothesis that the plasma projected by this gun comes off in an expanding torus which is shaped by its own magnetic field. When the plasma gun is fired into a dc magnetic field, the plasma forms a compact geometrical configuration (a plasma-magnetic entity called a plasmoid) which proceeds across the magnetic field. Plasmoids appear to be plasma cylinders elongated in the direction of the magnetic field. Plasmoids possess a measurable magnetic moment, a measurable translational speed, a transverse electric field, and a measurable size. Plasmoids can interact with each other, seemingly by reflecting off one another. Their orbits can also be made to curve toward one another. Plasmoids can be made to spiral to a stop if projected into a gas at about ${10}^{-3\mathrm{}}$ mm Hg pressure. Plasmoids can also be made to smash each other into fragments. There is some scant evidence to support the hypothesis that they undergo fission and possess spin.

• Received 21 June 1956

DOI:https://doi.org/10.1103/PhysRev.104.292