Definition: A toroidal reactor is a nuclear reactor shaped like a ring-shaped tube called a torus, which is filled with plasma. The nuclear reaction takes place within the plasma in the tube, kept in place by a magnetic field. If it had physical walls, they would melt, so the magnetic field acts like walls within the torus. Electrons circle inside the torus, heat and pressure makes the perfect environment for nuclear fusion to take place. Nuclear fusion is made possible because of the plasma creating heat and pressure. Toroidal reactors make nuclear fusion possible, in the past this was not possible to achieve this. The plasma is made by passing electricity through hydrogen atoms, this makes electrons ping off the hydrogen atoms, resulting in lots of free electrons within the plasma. The vacuum around the torus also adds to the heat and pressure, causing the electrons to escape from the hydrogen atoms, therefore making it possible to undergo nuclear fusion there.