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Purpose The aim of this paper is to present a method for calculating the electromagnetic fields, forces and current density distribution using Fourier series for a two-dimensional quasi steady state model consisting of a conducting uniform plate moving relative to an arbitrary current source with time harmonic excitation. Design/methodology/approach The presented solution is valid for an arbitrary source. A specific source is chosen consisting of a single coil made up of two-time harmonic current filaments. The solutions are derived and presented in a form that allows its expansion to include an arbitrary number of spatially shifted coils conducting arbitrary harmonic currents. Findings The analytical solution is compared to simulations produced using commercial finite element analysis software, ANSYS Maxwell2D and COMSOL, and is found to be in good agreement. The analytical solution provides a direct method to analyze the spatial harmonics in the system and can be computationally significantly faster especially at high relative speeds between the primary source and conducting plate. Originality/value The presented Fourier series solution is applied to simple 2-D model of a single coil with AC current excitation moving relative to a conducting plate. An analytical solution and analysis of this system has not been presented before, to the authors’ knowledge, using Fourier series or any other method.

Purpose This paper aims to present a method for calculating electromagnetic fields, eddy currents and forces for a quasi-static two-dimensional (2-D) model of linear induction motors (LIMs) where the primary side is modeled as a collection of individual coils. Design/methodology/approach An analytical solution using Fourier series is derived for a general source with current excitations residing in an airgap and moving relative to a conducting plate and back iron. Ideal magnetic material with infinite permeability is used to model the primary iron above the primary source and the back iron below the conducting plate. Findings The analytical solution is compared to a commercial 2-D finite element analysis (FEA) simulation for validation and then compared to a 2-D FEA model with a more detailed geometry of the LIM. The analytical model accurately predicts LIM thrust even though the geometry of the primary core is simplified as an infinitely long flat slab. 2-D frequency FEA can be used successfully to predict in motion LIM performance. Originality/value The analytical solution presented here models the primary excitations as individual discrete coils instead of current sheets, which all existing models are based on. The discrete coils approach provides a more intuitive and realistic model of the LIM.

 Abstract-Degradation and fouling of support structures in nuclear steam generators (SGs) can lead to SG tube damage and loss of SG efficiency. Inspection and monitoring of support structures combined with preventative maintenance programs can alleviate these effects and extend SG life. Conventional eddy current inspection technologies are extensively used for detecting and sizing indications from wall loss, frets at supports, cracks and other degradation modes in the tubes, as well as assessing the condition of support structures. However, these methods have limited capabilities when more than one degradation mode is present simultaneously, or when combined with fouling. Pulsed eddy current (PEC) combined with principal components analysis (PCA) was examined for inspection of 15.9 mm (5/8") Alloy-800 tubes and surrounding stainless steel (SS410) support structures. Clear separation of PCA scores associated with tubes from those associated with ferromagnetic SS410 supports permitted measurement of tube-to-support gaps, in either the presence of tube fretting or variation of relative position of the tube within SS410 supports. For concentric tubes, frets could be sized independently of SS410 hole diameter variations, which in other materials could represent support corrosion. Capability to clearly separate scores was attributed to large differences in relaxation times for diffusion of transient fields through the tube compared with diffusion into the ferromagnetic support structure.

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Abstract. Exact solutions for the electromagnetic response of a transmit-receive coil pair situated above two parallel plates separated by a gap, were developed using the recently published general model of Desjardins et al. that accounts for all electromagnetic interactions between the voltage-driven probe and the conducting samples. This model was then compared to the well-known model developed by Dodd and Deeds, which assumes a constant amplitude sinusoidal current and an open-circuit pick-up coil. Both models were compared with experimental results that measured the gap -materials simulated the electromagnetic properties of a Zr 2.5% Nb pressure tube and Zr-2 calandria tube, respectively, as found in the fuel channels of CANDU ® reactors. It was observed that while the Dodd and Deeds' model as applied to this work achieved a good shape agreement with experimental data for excitation frequencies at 2 kHz, at the higher frequency of 16 kHz good agreement was not achieved. In contrast, the model of Desjardin's et al., adapted for a transmitreceive probe configuration above two infinite flat plates, achieved an excellent shape agreement at both frequencies.

Self-organized field-reversed configuration (FRC)-like formation was observed after the super-sonic/Alfvénic collisional merging of two FRCs in the FAT-CM device at Nihon University. In this experiment, two FRCs were generated initially in two separate field-reversed theta-pinch type formation regions. Those two formation regions are coaxially connected to opposite ends of a cylindrical confinement chamber. The formed FRCs are oppositely-translated and collide in the middle of the confinement chamber at super-sonic/Alfvénic velocity. During the collision, the merged plasmoid experiences destructive disturbance and loses its fast toroidal flow and characteristic FRC property of having a field-reversed magnetic configuration to become a magnetized plasma without ordered structure. After this dynamic collision, a magnetic configuration of FRC with fast toroidal rotation is self-organized within a few tens of microseconds. This observation indicates robustness of the extremely high-beta, simple magnetic configuration.