The triple product is a figure of merit used for fusion plasmas, closely related to the Lawson Criteria. It specifies that successful fusion will be achieved when the product of the three quantities – n, the particle density of a plasma, the confinement time,τ and the temperature, T – reaches a certain value. Above this value of the triple product, the fusion energy released exceeds the energy required to produce and confine the plasma. For deuterium-tritium fusion this value is about : nτT ≥ 5×1021 m-3 s KeV. JET has reached values of nτT of over 1021 m-3 s KeV.