3D magnetic surfaces reconstruction in RFX-mod

The paper proposes an approach for the identification of magnetic surfaces, and particularly of the Last Closed Magnetic Surface, in nuclear fusion devices. The proposed method is based on a pure electromagnetic model without the requirement of information from the MHD. The methodology is based on the equivalent 3D representation of the plasma current by means of stream functions and an analytical description of 3D magnetic surfaces based on the 3D interpolation of magnetic field lines. The paper shows results achieved in a RFX-mod experimental shot, nevertheless the method is quite general and it can be applied to a wide range of fusion devices based on the magnetic confinement.