 That means that a machine with an average "q" = 2 might still be less than 1 in certain areas.In the 1970s, it was suggested that one way to counteract this and produce a design with a higher average "q" would be to shape the magnetic fields so that the plasma only filled the outer half of the torus, shaped like a D or C when viewed end-on, instead of the normal circular cross section.One of the first machines to incorporate a D-shaped plasma was the JET, which began its design work in 1973.