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Related papers: Magnetized cosmological perturbations

200 papers

Magnetic fields are believed to be generated in the cores of massive main sequence stars, and these may survive on to later stages of evolution. Observations of depressed dipole modes in red giant stars have been touted as evidence for…

Solar and Stellar Astrophysics · Physics 2020-03-11 Shyeh Tjing Loi

We present the formalism for the covariant treatment of gravitational radiation in a magnetized environment and discuss the implications of the field for gravity waves in the cosmological context. Our geometrical approach brings to the fore…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Christos G. Tsagas

Strong magnetic fields in the cores of stars are expected to significantly modify the behavior of gravity waves: this is likely the origin of suppressed dipole modes observed in many red giants. However, a detailed understanding of how such…

Solar and Stellar Astrophysics · Physics 2023-05-17 Nicholas Z. Rui , Jim Fuller

Despite the ever growing observational evidence for the existence of the large scale magnetic fields, their origin and the evolution are not fully understood. If the magnetic fields are of primordial origin, they result in the generation of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Yuki Shibusawa , Kiyotomo Ichiki , Kenji Kadota

The rich structure that we observe in molecular clouds is due to the interplay between strong magnetic fields and supersonic (turbulent) velocity fluctuations. The velocity fluctuations interact with the magnetic field, causing it too to…

Astrophysics of Galaxies · Physics 2020-08-12 James R. Beattie , Christoph Federrath , Amit Seta

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…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-11 Christos G. Tsagas

While magnetic fields have long been considered to be important for the evolution of magnetic non-degenerate stars and compact stars, it has become clear in recent years that actually all of the stars are deeply affected. This is…

Solar and Stellar Astrophysics · Physics 2021-02-03 Koh Takahashi , Norbert Langer

It is shown that gravitating magnetic fields affect the evolution of curvature perturbations in a way that is reminiscent of a pristine non-adiabatic pressure fluctuation. The gauge-invariant evolution of curvature perturbations is used to…

Astrophysics · Physics 2008-11-26 Massimo Giovannini

In the pre-recombination era, cosmological density fluctuations can naturally generate magnetic fields through Thomson scatterings. In previous studies, only the magnetic field generation from the initially-adiabatic fluctuations has been…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Satoshi Maeda , Keitaro Takahashi , Kiyotomo Ichiki

We investigate the possibility that electromagnetic fluctuations are amplified in expanding universe by parametric resonance, during the oscillatory regime of a scalar field to which they are coupled. We consider scalar electrodynamics and…

Astrophysics · Physics 2016-11-03 F. Finelli

We present a linear analysis of the vertical structure and growth of the magnetorotational instability in stratified, weakly ionised accretion discs, such as protostellar and quiescent dwarf novae systems. The method includes the effects of…

Astrophysics · Physics 2009-11-10 Raquel Salmeron , Mark Wardle

The excitation of low frequency plasma waves in an expanding anisotropic cosmological model which contains a magnetic field frozen into the matter and pointing in the longitudinal direction is discussed. Using the exact equations governing…

Astrophysics · Physics 2009-11-07 Demetrios Papadopoulos , Loukas Vlahos , F. Paul Esposito

The generation of large-scale magnetic fields is studied in dilaton electromagnetism in inflationary cosmology, taking into account the dilaton's evolution throughout inflation and reheating until it is stabilized with possible entropy…

Astrophysics · Physics 2008-11-26 Kazuharu Bamba , J. Yokoyama

The small-scale turbulent dynamo is a key mechanism for amplifying galactic magnetic fields, yet the resulting field morphology remains poorly understood. Using 3D driven turbulence simulations across a range of compressibilities,…

Astrophysics of Galaxies · Physics 2026-03-25 Sasi M. Behara , Amit Seta

As well known, magnetic fields in space are distributed very inhomogeneously. Some-times field distributions have forms of filaments with high magnetic field values. As many ob-servations show, such a filamentation takes place in convective…

Solar and Stellar Astrophysics · Physics 2024-03-03 Evgeny A. Kuznetsov , Evgeny A. Mikhailov

If the large-angular-scale anisotropy in the cosmic microwave background radiation is caused by the long-wavelength cosmological perturbations of quantum mechanical origin, they are, most likely, gravitational waves, rather than density…

General Relativity and Quantum Cosmology · Physics 2010-11-19 L. P. Grishchuk

The effect of a magnetic field on the linear phase of the advective-acoustic instability is investigated, as a first step toward a magnetohydrodynamic (MHD) theory of the stationary accretion shock instability taking place during stellar…

Solar and Stellar Astrophysics · Physics 2014-11-20 Jerome Guilet , Thierry Foglizzo

Gravitational waves are propagating undulations in the spacetime fabric, which interact very weakly with their environment. In cosmology, gravitational-wave distortions are produced by most of the inflationary scenarios and their…

General Relativity and Quantum Cosmology · Physics 2016-03-30 Despoina Pazouli , Christos G. Tsagas

If cosmic magnetic fields are indeed produced during inflation, they are likely to be correlated with the scalar metric perturbations that are responsible for the Cosmic Microwave Background anisotropies and Large Scale Structure. Within an…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Rajeev Kumar Jain , Martin S. Sloth

Motivated by the isotropy of the CMB spectrum, all existing studies of magnetised cosmological perturbations employ FRW backgrounds. However, it is important, to know the limits of this approximation and the effects one loses by neglecting…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Christos Tsagas , Roy Maartens