Poloidal field equilibrium calculations for JET

The structure of the JET 2D Poloidal Field Analysis Package is discussed. The ability to cope with different plasma current density distributions (skin, flat or peaked), each with a range of Beta poloidal values and varying plasma shapes is a new feature of these calculations. It is possible to construct instant-by-instant pictures of equilibrium configurations for various plasma build up scenarios taking into account the level of flux in the iron core and return limbs. The equilibrium configurations are calculated for two possible sequences of plasma build up. Examples of the magnetic field calculations being carried out under contract to JET at the Rutherford Laboratory, using a 3D code, are also given