Progress on interaction between NTM Island and heavy impurities in AUG

The use of Tungsten in plasma facing component in nowadays and future tokamaks is considered a solution for the problems of heat load on the walls and of Tritium retention. In some JET discharges Tungsten accumulates in the plasma core, with the possibility of leading to radiation collapse and possibly disruption. This accumulation seems exacerbated by the presence of a magnetic island. To get an insight in this phenomenon through comparison with other machines, we model an AUG discharge where both Tungsten core accumulation and a (3,2) island are present. The underlying idea is that the onset of the mode suddenly changes the transport in its radial position by short-circuiting the region where W is present with a more central region where inward neoclassical transport dominates. We use ASTRA (a 1.5-dimensional transport code calculating the evolution of plasma parameters in a time dependent axisymmetric MHD equilibrium configuration) with transport coefficients calculated from NCLASS and TGLF. We initialise the simulation with experimental profiles. We model the island as an enhanced diffusion zone; its radial position, onset time and width are determined from experimental data (Mirnov coils and ECE fluctuations). We compare the Tungsten SXR emissivity from the computed density (synthetic diagnostic) with the experimental SXR signals. We will report on the simulation results and the status of the synthetic diagnostic.