Can the observed large scale magnetic fields be seeded by helical primordial fields?

Abstract

Gravitational wave production induces a strong constraint on the amplitude of a primordial magnetic field. It has been shown that the nucleosynthesis bound for a stochastic gravitational wave background implies that causally generated fields cannot have enough power on large scales to provide the seeds necessary for the observed magnetic fields in galaxies and clusters, even by the most optimistic dynamo amplification. Magnetic fields generated at inflation can have high enough amplitude only if their spectrum is very red. Here we show that helicity, which leads to an inverse cascade, can mitigate these limits. In particular, we find that helical fields generated at the QCD phase transition or at inflation with red spectrum are possible seeds for the dynamo. Helical fields generated at the electroweak phase transition are instead excluded as seeds at large scales. We also calculate the spectrum of gravitational waves generated by helical magnetic fields.

41 pages, 12 figures

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Cited by in corpus (29)

• Cosmological Magnetic Fields: Their Generation, Evolution and Observation
• Universal infrared scaling of gravitational wave background spectra
• Adding helicity to inflationary magnetogenesis
• The Gravitational-Wave Physics II: Progress
• Magnetohydrodynamics of Chiral Relativistic Fluids
• NANOGrav signal from MHD turbulence at QCD phase transition in the early universe
• Primordial magnetic field limits from cosmological data
• Generation of gravitational waves from freely decaying turbulence
• Laminar and turbulent dynamos in chiral magnetohydrodynamics. II. Simulations
• Numerical simulations of the decay of primordial magnetic turbulence
• Scale-invariant Helical Magnetic Fields from Inflation
• Cosmological Magnetogenesis From Extra-dimensional Gauss Bonnet Gravity
• The Evolution of the Large-Scale Tail of Primordial Magnetic Fields
• Evolution of Helical Cosmic Magnetic Fields as Predicted by Magnetohydrodynamic Closure Theory
• The Cosmological QCD Phase Transition Revisited
• Cosmological magnetic fields from inflation in extended electromagnetism
• Anomaly-driven inverse cascade and inhomogeneities in a magnetized chiral plasma in the early Universe
• Helical magnetic fields from Riemann coupling
• Helical cosmological magnetic fields from extra-dimensions
• Gravitational waves from cosmological phase transitions
• Modified Magnetohydrodynamics Around the Electroweak Transition
• Helical magnetic fields from Riemann coupling lead to baryogenesis
• Completing magnetic field generation from gravitationally coupled electrodynamics with the curvaton mechanism
• Electroweak baryogenesis via chiral gravitational waves
• Charge asymmetry from CP-violating fermion scattering off bubble walls during the electroweak phase transition
• Cosmological Ohm's law and dynamics of non-minimal electromagnetism
• Magnetogenesis from isocurvature initial conditions
• Gravitational Waves sourced by Gauge Fields during Inflation
• A narrow-band parameterization for the stochastic gravitational wave background