Journal Article

A Fast Matrix Compression Method for Large Scale Numerical Modelling of Rotationally Symmetric 3D Passive Structures in Fusion Devices

Rubinacci, Guglielmo, Tamburrino, Antonello, Chiariello, Andrea Gaetano, Cau, Francesca, Scalera, Valentino, Ventre, Salvatore, Villone, Fabio

2022

Overview

This paper illustrates the development of a recursive QR technique for the analysis of transient events, such as disruptions or scenario evolution, in fusion devices with three-dimensional conducting structures using an integral eddy current formulation. An integral formulation involves the solution, at each time step, of a large full linear system. For this reason, a direct solution is impractical in terms of time and memory consumption. Moreover, typical fusion devices show a symmetric/periodic structure. This can be properly exploited when the plasma and other sources possess the same symmetry/periodicity of the structure. Indeed, in this case, the computation can be reduced to only a single sector of the overall structure. In this work the periodicity and the symmetries are merged in the recursive QR technique, exhibiting a huge decrease in the computational cost. Finally, the proposed technique is applied to a realistic large-scale problem related to the International Thermonuclear Experimental Reactor (ITER).

• Publisher: MDPI AG
• Subject: eddy current / Electrodes / fast methods / Fourier transforms / H-matrix / integral formulations / Magnetic fields / Plasma / plasma fusion / QR-MGS sparsification