Magnetic coupling to the Advanced Virgo payloads and its impact on the low frequency sensitivity

TL;DR

This paper investigates electromagnetic coupling effects on the Advanced Virgo gravitational wave detector's payloads using finite element analysis, estimating magnetic noise contributions and assessing their impact on low-frequency sensitivity.

Contribution

It introduces a validated finite element model to estimate magnetic coupling and noise in the Advanced Virgo payloads, providing insights into potential low-frequency sensitivity impacts.

Findings

Finite element model accurately represents electromagnetic coupling.

Magnetic noise currently negligible but may become significant at design sensitivity.

21 electrical configurations compatible with measurements were identified.

Abstract

We study the electromagnetic coupling of the Advanced Virgo (AdV) Input Mirror Payload (IMP) in response to a slowly time-varying magnetic field. As the problem is not amenable to analytical solution, we employ and validate a finite element (FE) analysis approach. The FE model is built to represent as faithfully as possible the real object and it has been validated by comparison with experimental measurements. The intent is to estimate the induced currents and the magnetic field in the neighbourhood of the payload. The procedure found 21 equivalent electrical configurations that are compatible with the measurements. These have been used to compute the magnetic noise contribution to the total AdV strain noise. At the current stage of development AdV seems to be unaffected by magnetic noise, but we foresee a non-negligible coupling once AdV reaches the design sensitivity.