Dark photon limits from magnetic fields and astrophysical plasmas

TL;DR

This paper investigates the influence of dark photons on astrophysical plasmas and magnetic fields, concluding that their effects are negligible and providing updated bounds based on recent Juno data.

Contribution

The study demonstrates that dark photon effects on plasma dynamics are negligible and refines existing bounds using recent spacecraft data.

Findings

Dark photon effects on plasma are negligible.

Existing bounds from Pioneer 10 are unreliable.

New limits are set using Juno data.

Abstract

Dark photons may kinetically mix with our photon and modify Maxwell's equations. We examine their impact on the Lorentz force acting on the plasma in astrophysical magnetospheres. Solving the relevant magnetohydrodynamic equations, we show that any dark photon effect is negligible. The existing bound on dark photons with a mass below $10^{-14}$ eV, coming from Pioneer 10 observations of Jupiter's magnetosphere, relies on such an effect and is thus unreliable. To rectify this, we use recent Juno analyses to isolate any dark photon-induced modification of the Jovian magnetic field and hence place a numerically similar limit.