Eur. Phys. J. D 35, 59-67 (2005)
https://doi.org/10.1140/epjd/e2005-00188-3

Magnetostatic field noise near metallic surfaces

¹ Institut für Physik, Universität Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany
² Laboratoire Charles Fabry de l'Institut d'Optique, B.P. 147, 91403 Orsay Cedex, France

Corresponding author: ^a carsten.henkel@physik.uni-potsdam.de

Received: 25 March 2005
Published online: 19 July 2005

Abstract

We develop an effective low-frequency theory of the electromagnetic field in equilibrium with thermal objects. The aim is to compute thermal magnetic noise spectra close to metallic microstructures. We focus on the limit where the material response is characterised by the electric conductivity. At the boundary between empty space and metallic microstructures, a large jump occurs in the dielectric function which leads to a partial screening of low-frequency magnetic fields generated by thermal current fluctuations. We resolve a discrepancy between two approaches used in the past to compute magnetic field noise spectra close to microstructured materials.