Fast identification problems in 3D iron core fusion devices

In nuclear fusion devices, unknown currents modelling the plasma behavior have to be estimated within the strict instability growth time, because of both control and stabilization requirements. Nowadays, suitable identification procedures mainly based on information coming from the magnetic measurements are available, typically in the axisymmetric frame. The presence of iron materials strongly increases the complexity for the lack of both linear behavior and 2D hypothesis. The paper proposes and compares two effective iron modeling and assesses their suitability for practical applications.