1,355,262 research outputs found
An analytical demonstration of coupling schemes between magnetohydrodynamic codes and eddy current codes
No full textIn order to model a magnetohydrodynamic (MHD) instability that strongly couples to external conducting structures (walls and/or coils) in a fusion device, it is often necessary to combine a MHD code solving for the plasma response, with an eddy current code computing the fields and currents of conductors. We present a rigorous proof of the coupling schemes between these two types of codes. One of the coupling schemes has been introduced and implemented in the CARMA code {[}R. Albanese, Y. Q. Liu, A. Portone, G. Rubinacci, and F. Villone, IEEE Trans. Magn. 44, 1654 (2008); A. Portone, F. Villone, Y. Q. Liu, R. Albanese, and G. Rubinacci, Plasma Phys. Controlled Fusion 50, 085004 (2008)] that couples the MHD code MARS-F {[}Y. Q. Liu, A. Bondeson, C. M. Fransson, B. Lennartson, and C. Breitholtz, Phys. Plasmas 7, 3681 (2000)] and the eddy current code CARIDDI {[}R. Albanese and G. Rubinacci, Adv. Imaging Electron Phys. 102, 1 (1998)]. While the coupling schemes are described for a general toroidal geometry, we give the analytical proof for a cylindrical plasma
A new non-iterative inversion method for Electrical Resistance Tomography
No full textIn this paper, the inverse problem of resistivity retrieval is addressed in the frame of electrical resistance tomography (ERT). The ERT data is a set of measurements of the dc resistances between pairs of electrodes in contact with the conductor under investigation. This paper is focused on a non-iterative inversion method based on the monotonicity, of the resistance matrix (and of its numerical approximations). The main features of the proposed inversion method are its low computational cost requiring the solution of O(n) direct problems, where n is the number of parameters used to represent the unknown resistivity, and its very simple numerical implementation
Automatic treatment of multiply connected regions in Integral Formulations
No full textThis paper deals with the volume integral formulation of the eddy current problem in terms of the electric vector potential. Its aim is to present a simple topological algorithm for finding the additional degrees of freedom required in the discretization of a multiply connected region when using edge elements. The algorithm is completely automatic and it is based, as other previous approaches, on the application of the spanning tree technique on the graph made by the edges and nodes of the finite element mesh lying on the boundary surface of the conducting domain
A Broadband Volume Integral Formulation Based on Edge-Elements for Full-Wave Analysis of Lossy Interconnects
No full textA new numerical fully three-dimensional (3-D) volume integral formulation for the electromagnetic analysis from static to microwave frequencies of penetrable materials (dielectric, eventually lossy, and conductors with finite conductivity) is here discussed. Its key feature is the introduction of a volumetric loop-star decomposition for treating piecewise homogeneous materials. The associated shape functions have been determined to decompose the volume current density in a solenoidal and a nonsolenoidal part, in analogy to the surface loop-star shape functions, used for modeling surface current densities on perfect electric conductors. The possibility of modeling volumetric ohmic and polarization current densities allows to compute in an accurate way the electromagnetic field in complex 3-D geometries, such as high speed interconnects, on a broad range of frequencies
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