Calibration Of Magnetic Field Probes Using 3D Simulations
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Authors
Arnot, Nicolas
Date
Type
thesis
Language
eng
Keyword
Fusion Energy , Plasma Diagnostics , Magnetic Field Sensors , Electromagnetism , Finite Element Analysis
Alternative Title
Abstract
Inductive magnetic field sensors (B-probes, Mirnov coils) are important diagnostic tools in plasma experiments, critical to the identification of instabilities and in the reconstruction of equilibrium states. Inserting a B-probe directly into a fusion relevant plasma would degrade the device, meaning these probes need appropriate shielding. Common approaches include a protective coating around the probe, placement behind thermal plates, or placement within recessed wells in the confinement chamber walls. Various methods have been developed to calibrate B-probes shielded in these ways, converting the induced voltages at their protected locations to meaningful magnetic field strength measurements.
General Fusion, in pursuit of magnetized target fusion, requires B-probes shielded by metallic sheaths to be placed within recessed wells in the chamber wall. This creates a complex propagation geometry for the magnetic fields, and limits the applicability of established calibration methods. This project investigates the viability of using 3D magnetic field simulations to calibrate B-probes within the General Fusion shielding geometry.
A physical calibration experiment was performed, then modelled within COMSOL Multiphysics. The simulated B-probe voltages were compared against experimental results to determine the accuracy of the simulations. Normalized voltage profiles agreed within the sensitivity range of the simulations, showing this approach can be used to determine a frequency dependent calibration factor for each probe. Radial profiles were developed to relate the magnetic field strength within the wells to that within the body of the calibration chamber.
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Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
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Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution 4.0 International
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution 4.0 International