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We study the evolution of primordial magnetic fields until the recombination epoch, which is constrained by the conservation of magnetic helicity density if they are maximally helical and by the Hosking integral if they are non-helical. We…

宇宙学与河外天体物理 · 物理学 2025-08-07 Fumio Uchida , Motoko Fujiwara , Kohei Kamada , Jun'ichi Yokoyama

We study the evolution of phase-transition-generated cosmic magnetic fields coupled to the primeval cosmic plasma in turbulent and viscous free-streaming regimes. The evolution laws for the magnetic energy density and correlation length,…

宇宙学与河外天体物理 · 物理学 2015-06-15 Leonardo Campanelli

We extend our recent derivation of the time evolution equations for the energy content of magnetic fields and turbulent motions for incompressible, homogeneous, and isotropic turbulence to include the case of nonvanishing helicity. These…

宇宙学与河外天体物理 · 物理学 2013-06-14 Andrey Saveliev , Karsten Jedamzik , Guenter Sigl

We consider the evolution of primordial magnetic fields generated during cosmological, electroweak or QCD, phase transitions. We assume that the magnetic field generation can be described as an injection of magnetic energy to cosmological…

宇宙学与河外天体物理 · 物理学 2013-04-24 Tina Kahniashvili , Alexander G. Tevzadze , Axel Brandenburg , Andrii Neronov

We study the evolution of primordial magnetic fields in an expanding cosmic plasma. For this purpose we present a comprehensive theoretical model to consider the evolution of MHD turbulence that can be used over a wide range of physical…

宇宙学与河外天体物理 · 物理学 2016-10-12 Tina Kahniashvili , Axel Brandenburg , Alexander G. Tevzadze

Motivated by a scenario of magnetogenesis in which a homogeneous magnetic field is generated during inflation, we study the magnetohydrodynamic evolution of the primordial plasma motions for two kinds of initial conditions -- (i) a…

宇宙学与河外天体物理 · 物理学 2020-07-28 Axel Brandenburg , Ruth Durrer , Yiwen Huang , Tina Kahniashvili , Sayan Mandal , Shinji Mukohyama

The decay of a turbulent magnetic field is slower with helicity than without. Furthermore, the magnetic correlation length grows faster for a helical than a nonhelical field. Both helical and nonhelical decay laws involve conserved…

等离子体物理 · 物理学 2025-01-08 Axel Brandenburg , Aikya Banerjee

The Hosking integral, which characterizes magnetic helicity fluctuations in subvolumes, is known to govern the decay of magnetically dominated turbulence. Here we show that, when the evolution of the magnetic field is controlled by the…

等离子体物理 · 物理学 2023-09-14 Axel Brandenburg

Primordial magnetic fields could explain the large-scale magnetic fields present in the Universe. Inflation and phase transitions in the early Universe could give rise to such fields with unique characteristics. We investigate the…

We examine the evolution of magnetic fields in an expanding fluid composed of matter and radiation with particular interest in the evolution of cosmic magnetic fields. We derive the propagation velocities and damping rates for relativistic…

天体物理学 · 物理学 2009-10-28 K. Jedamzik , V. Katalinic , A. Olinto

(abridged) A detailed examination of the evolution of stochastic magnetic fields between high cosmic temperatures and the present epoch is presented. A simple analytical model matching the results of the 3D MHD simulations allows for the…

天体物理学 · 物理学 2009-11-10 Robi Banerjee , Karsten Jedamzik

Powerful lasers may in future produce magnetic fields that would allow us to study turbulent magnetohydrodynamic inverse cascade behavior. This has so far only been seen in numerical simulations. In the laboratory, however, the produced…

等离子体物理 · 物理学 2025-08-04 Axel Brandenburg , Longqing Yi , Xianshu Wu

The evolution and viscous damping of cosmic magnetic fields in the early universe, is analysed. Using the fact that the fluid, electromagnetic, and shear viscous energy-momentum tensors are all conformally invariant, the evolution is…

天体物理学 · 物理学 2011-09-29 Kandaswamy Subramanian , John D. Barrow

We study the evolution of a stochastic helical magnetic field generated in the early Universe after the electroweak phase transition, using standard magnetohydrodynamics (MHD). We find how the coherence length xi, magnetic energy E_M and…

天体物理学 · 物理学 2017-08-23 Mark Hindmarsh , M. Christensson , A. Brandenburg

We present new simulations of decaying hydromagnetic turbulence for a relativistic equation of state relevant to the early universe. We compare helical and nonhelical cases either with kinetically or magnetically dominated initial fields.…

宇宙学与河外天体物理 · 物理学 2017-12-29 Axel Brandenburg , Tina Kahniashvili , Sayan Mandal , Alberto Roper Pol , Alexander G. Tevzadze , Tanmay Vachaspati

Some common properties of helical magnetic fields in decaying and driven turbulence are discussed. These include mainly the inverse cascade that produces fields on progressively larger scales. Magnetic helicity also restricts the evolution…

天体物理学 · 物理学 2007-05-23 Axel Brandenburg

We study the evolution of magnetic fields in freely decaying magnetohydrodynamic turbulence. By quasi-linearizing the Navier-Stokes equation, we solve analytically the induction equation in quasi-normal approximation. We find that, if the…

天体物理学 · 物理学 2009-06-23 Leonardo Campanelli

In helical hydromagnetic turbulence with an imposed magnetic field (which is constant in space and time) the magnetic helicity of the field within a periodic domain is no longer an invariant of the ideal equations. Alternatively, there is a…

天体物理学 · 物理学 2009-11-07 Axel Brandenburg , William H. Matthaeus

We perform direct numerical simulations of forced and freely decaying 3D magnetohydrodynamic turbulence in order to model magnetic field evolution during cosmological phase transitions in the early Universe. Our approach assumes the…

宇宙学与河外天体物理 · 物理学 2010-11-30 Tina Kahniashvili , Axel Brandenburg , Alexander G. Tevzadze , Bharat Ratra

We analyse the evolution of primordial magnetic fields in spatially flat Friedmann universes and reconsider the belief that, after inflation, these fields decay adiabatically on all scales. Without~abandoning classical electromagnetism or…

宇宙学与河外天体物理 · 物理学 2017-05-11 Christos G. Tsagas
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