Improved field post‐processing for a Stern–Gerlach magnetic deflection magnet

Abstract

SUMMARYA Stern–Gerlach magnet applies a field gradient in order to deflect particles such that their magnetic moment can be determined. The design of such magnets is based on finite‐element (FE) simulations of the magnetic field and its gradient. However, inaccuracies arise when these quantities are calculated from an FE solution for the magnetic vector potential by numerical differentiation. For first‐order FE shape functions, the discretisation error for the field gradient may even fail to converge. An improved post‐processing approach marks a region in the magnet aperture where the field is post‐processed by matching a local analytical solution with the obtained FE solution. The local solution allows to derive values for the magnetic field and its gradient without reducing the convergence order of the discretisation error. The method is validated against the analytic solution for a two‐wire configuration and is applied for the design of a Rabi‐type Stern–Gerlach magnet. Copyright © 2013 John Wiley & Sons, Ltd.

Design of a Strong Gradient Magnet for the Deflection of Nanoclusters

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Nonlinear semi-classical 3D quantum spin

“…Since a full representation of the magnetic field was needed, and there exist a magnetic field prior to the spin entering the Stern-Gerlach device, the full magnetic field is calculated. Although some have calulated a 2D magnetic field using a finite element method [10], the complete 3D magnetic field was obtained by the Biot-Savart law:…”

A defect corrected finite element approach for the accurate evaluation of magnetic fields on unstructured grids

“…) [7], where |Ω 0 | refers to the size of the domain Ω 0 . Contrary to the Fourier coefficients, (37) is a nonlinear quantity of interest with respect to the solution u 0 .…”

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