A general method for computing thermal magnetic noise arising from thin conducting objects

Joonas Iivanainen*, Antti J. Mäkinen, Rasmus Zetter, Koos C.J. Zevenhoven, Risto J. Ilmoniemi, Lauri Parkkonen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Thermal motion of charge carriers in a conducting object causes magnetic field noise that may interfere with sensitive measurements near the object. In this paper, we describe a method to compute the spectral properties of the thermal magnetic noise from arbitrarily shaped thin conducting objects. The method is based on modeling divergence-free currents on a conducting surface using a stream function and calculating the magnetically independent noise-current modes. By doing this, we obtain the power spectral density of the thermal magnetic noise as well as its spatial correlations and frequency dependence. We also describe a numerical implementation of the method and verify it against analytic formulas. We provide the implementation as a part of the free and open-source software package bfieldtools.

Original languageEnglish
Article number043901
Number of pages10
JournalJournal of Applied Physics
Volume130
Issue number4
DOIs
Publication statusPublished - 28 Jul 2021
MoE publication typeA1 Journal article-refereed

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