A CT containment system for plasma asymmetrically toroidally shaped by the containment, was first introduced into thought as a concept by Alfvén. The two examplar types; Field-reversed configuration plasma with a null toroid, firstly, is generally produced by prolate-theta-pinches with the necessarily existing field condition where the field magnetic bias is in a reversed situation. The second type has a non-null toroid, known as a spheromak configuration, is similar in arrangement to a smoke ring. The FRC is also toroidal, but extended into a tubular shape or hollow cylinder. The main difference between the two is that the spheromak contains poloidal (vertical rings) and toroidal (horizontal) magnetic fields, while the FRC has only the poloidal fields and requires an external magnet for confinement. In both cases the combination of electrical currents and their associated magnetic fields result in a series of closed magnetic lines that maintains the ring shape, without the need for magnets in the center of the plasma (unlike a tokamak).