Status of the halo current sensor project for JET-EP

Halo currents (HCs), flowing through the plasma and the vacuum vessel during plasma disruptive events, induce severe mechanical stresses in the plasma facing components and in the vessel, and are a major concern for present and future fusion experiments like ITER. The new system of halo current sensors (HCS) designed for JET-EP (enhanced performance, EP) should help to evaluate HC density distribution, localization and rotation as well as toroidal and poloidal current asymmetries. The HCS system will include four identical mechanical structures each including eight Rogowski coils and two toroidal pick-up coils. The Rogowski coils will measure directly the current flowing through some of the tiles of the upper dump plate. The toroidal field pick-up coils will estimate the total poloidal HC. The coil assemblies are installed at the top of the vessel close to secondary X-point in four octants equally spaced along the toroidal coordinate. In the paper, the design and the manufacturing of the HCS system are presented in detail. (c) 2005 Elsevier B.V. All rights reserved.