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With reference to toroidal fusion devices, we solve axisymmetric nonlinear evolutionary equilibrium equations, describing the plasma behaviour, self-consistently coupled to eddy currents equations, describing surrounding three-dimensional (3D) structures. This formulation allows the analysis of nonlinear plasma quasi-static evolution in the presence of 3D volumetric conductors. Several validations and test cases are presented, suggesting the potential applications of the proposed method to the analysis of various situations of scientific and technical interest for future fusion devices such as ITER and DEMO, like for instance disruptions.

The vertical stability of the Experimental Advanced Superconducting Tokamak (EAST) is studied in detail in the present paper. It is found that correct modelling of the detailed three-dimensional (3D) features of the conducting structures surrounding the plasma is essential in order to get reliable estimates of the growth rate of vertical displacement events. The numerical model developed, based on the CarMa0 code, can take 3D effects into account, and provides results very close to experimental values for a wide range of plasma configurations. A deep insight about the current density patterns induced in passive structures is gained.

Heat and particle loads on the plasma facing components are among the most challenging issues to be solved for a reactor design. Alternative magnetic configurations may enable tokamak operation with a lower peak heat load than a standard single null (SN) divertor. This papers reports on the creation and control of one of such alternatives: a two-null nearby divertor configuration. An important element of this study is that this two-null divertor was produced on a large superconducting tokamak as an experimental advanced superconducting tokamak. A preliminary experiment with the second null forming a configuration with significant distance between the two nulls and a contracting geometry near the target plates was performed in 2014. These configurations have been designed using the FIXFREE code and optimized with CREATE-NL tools and are discussed in the paper. Predictive edge simulations using the TECXY code are also presented by comparing the advanced divertor and SN configuration. Finally, the experimental results of ohmic and low confinement (L-mode) two-null divertor and SN discharges and interpretative two-dimensional edge simulations are discussed. Future experiments will be devoted to varying the distance between the two nulls in high confinement (H-mode) discharges.

We report on further measurements and a numerical solution for a proposed benchmark problem involving an eddy-current nondestructive evaluation configuration. This is a simplified version of the inspection of fastener holes in aircraft structures, comprising combinations of plates with through holes and a crack. Previously, only line (B-scan) data were provided for the coil impedance, while in this paper, we provide precision surface (C-scan) data as well as details on the evaluation of the critical parameters of the problem. Furthermore, the experimental data are cross validated with numerical ones using a model that combines an integral formulation and the FEM approach.