Article

# Magnetic field calculations including the impact of persistent currents in superconducting filaments

CERN, Geneva

IEEE Transactions on Magnetics (Impact Factor: 1.42). 04/2002; DOI: 10.1109/20.996213 Source: IEEE Xplore

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**ABSTRACT:**The program package ROXIE [1] has been developed at CERN for the design and optimization of the superconducting magnets for the LHC.The necessity of extremely uniform (coil dominated) fields in accelerator magnets requires very accurate methods of .eld computation. For this purpose a coupled boundary-element/ finite-element technique (BEM-FEM) is used [2]. Quadrilateral higher order finite-elements are used for the discretization of the iron domain.This is necessary for the accurate modeling of the iron contours and is favorable for 3D meshes. A new quadrilateral mesh generator using geometrically optimized domain decomposition which was developed at the University of Stuttgart, Germany [3] has been implemented into the ROXIE program providing fully automatic and user friendly mesh generation.The frequent application of mathematical optimization techniques requires parametric models which are set-up using a feature-based approach.The structure of the magnet cross-section can be modeled using parametric objects such as holes of different forms, elliptic, parabolic or hyperbolic arcs, notches, slots,etc. Investigations of the speed-up of the computations due to geometrically optimized meshes will be presented. For sensitivity analysis, point based morphing algorithms are applied to the generated mesh.IEEE Transactions on Applied Superconductivity 04/2002; · 1.20 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**Fast-ramping superconducting (SC) accelerator magnets are the subject of R&D efforts at various laboratories. The simulation of field quality in fast-ramping magnets requires modifications of magnet design tools such as the CERN field computation program ROXIE. In this paper we present the efforts towards dynamic 2-D simulations of fast-ramping SC magnets. Models for persistent currents, inter-strand coupling currents, inter-filament coupling currents, and for eddy-currents in conducting coil-wedges are described and validated.IEEE Transactions on Applied Superconductivity 07/2008; · 1.20 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**Fast-ramping superconducting (SC) accelerator magnets are the subject of R&D efforts by magnet designers at various laboratories. They require modifications of magnet design tools such as the ROXIE program at CERN, i.e. models of dynamic effects in superconductors need to be implemented and validated. In this paper we present the efforts towards a dynamic 2-D simulation of fast-ramping SC magnets with the ROXIE tool. Models are introduced and simulation results are compared to measurements of the GSI001 magnet of a GSI test magnet constructed and measured at BNL.

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