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

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 method to compute spectral properties thermal from arbitrarily shaped thin objects. The is based on modeling divergence-free currents surface using stream function and calculating magnetically independent noise-current modes. By doing this, obtain power density as well its spatial correlations frequency dependence. We also numerical implementation verify it against analytic formulas. provide part free open-source software package bfieldtools.