Shakeib Arshad

JET Enhancement Programmes: key steps in the preparation of ITER

Since 2000, the JET Facilities have been exploited under the European Fusion Development Agreement (EFDA) and have played a key role in the preparation of ITER, in particular by operating in deuterium/tritium plasmas, optimising remote handling and consolidating ITER operating scenarios with increasing heating power. JET has undergone significant enhancement during this period. A first enhancement programme is now approaching fruition as the present shutdown nears an end. The experimental campaigns are due to resume in November 2005 with an improved divertor, increased heating power and around 20 new diagnostics. A second enhancement programme, to be completed by the end of 2008, is already underway, and will enable major experiments in support of ITER. This includes the installation of a new first wall with an ITER-like materials combination, a further upgrade of the neutral beams, an upgraded plasma control system, a high frequency pellet injector and a number of diagnostics key for ITER technology and physics

Model Based Estimation Of The Eddy Currents For The Iter Tokamak

Eddy currents flowing in the conductive structures surrounding the plasma in a tokamak affect magnetic measurements (magnetic fields and fluxes at given points), which are used to estimate plasma quantities such as plasma toroidal current, position and shape. Due to their spatial distribution and their fast variations, eddy currents are difficult sources to characterize. This is particularly true when magnetic sensors are outside the conductive plasma chamber implying that eddy currents flow between the so-called measurement contour and the plasma region. As a matter of fact many plasma shape identification algorithms assume the plasma current distribution as the only magnetic source located inside the measurement contour. In this paper we deal with the problem of estimating eddy currents in the ITER tokamak by means of a dynamic observer to wash out their contribution to magnetic measurements.