Thermal generation of cosmological seed magnetic fields in ionization fronts

Subramanian, Kandaswamy; Narasimha, D.; Chitre, S. M.

doi:10.1093/mnras/271.1.l15

Cited by 110 publications

(89 citation statements)

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“…This explains why our model leads to orders of magnitude higher predictions than in [23]. Thus, the mechanism we described in this paper is likely to be dominant in cosmological situations where strong anisotropic and inhomogeneous radiation pressure exists.…”

Section: Discussionmentioning

confidence: 62%

Cosmological magnetogenesis driven by radiation pressure

2003

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The origin of large scale cosmological magnetic fields remains a mystery, despite the continuous efforts devoted to that problem. We present a new model of magnetic field generation, based on local charge separation provided by an anisotropic and inhomogeneous radiation pressure. In the cosmological context, the processes we explore take place at the epoch of the reionisation of the Universe. Under simple assumptions, we obtain results (i) in terms of the order of magnitude of the field generated at large scales and (ii) in terms of its power spectrum. The amplitudes obtained (B ∼ 8. 10 −6 µG) are considerably higher than those obtained in usual magnetogenesis models and provide suitable seeds for amplification by adiabatic collapse and/or dynamo during structure formation.PACS numbers: 95.30.Qd

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Section: Discussionmentioning

confidence: 62%

Cosmological magnetogenesis driven by radiation pressure

2003

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“…This can be obtained from the Bianchi identities (19) where ǫ ijk is the Levi-Cività tensor and B i ≡ ǫ ijk F jk /2 is comoving magnetic field. We can expand the photon energy density, fluid velosities and photon anisotropic stress as…”

Section: Formulationmentioning

confidence: 99%

Magnetic Field Generation from Cosmological Perturbations

et al. 2005

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In this letter, we discuss generation of magnetic field from cosmological perturbations. We consider the evolution of three component plasma (electron, proton and photon) evaluating the collision term between elecrons and photons up to the second order. The collision term is shown to induce electric current, which then generate magnetic field. There are three contributions, two of which can be evaluated from the first-order quantities, while the other one is fluid vorticity which is purely second order. We estimate the magnitudes of the former contributions and shows that the amplitude of the produced magnetic field is about ∼ 10 −19 G at 10Mpc comoving scale at the decoupling. Compared to astrophysical and inflationary mechanisms for seed-field generation, our study suffers from much less ambiguities concerning unknown physics and/or processes.

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“…Several mechanisms to produce the seed fields at different epochs of the universe have been proposed, for example, Harrison (1973) aregued that turbublence in the radiation-dominated era produces the weak seed fields of presently 10 −8 G; Hogan (1983) gave a basic argument for considering phase transition as a potential mechanism for the generation of primordial magnetic fields; Turner and Widrow (1988) proposed an inflation scenario for the creation of primordial magnetic fields; Quashnock et al (1989) considered the thermoelectric effect in QCD phase transition to generate the magnetic field of 2 × 10 −17 G in the early universe; Wiechan et al (1998) showed that the plasma-neutral gas friction in a weakly ionized rotating protogalactic system creates the seed magnetic fields. The Biermann battery in ionization fronts can in principle produce reasonably strong magnetic fields (see Subramanian et al 1994;Gnedin et al 2000). Magnetic fields could originate deep in the early phases of the universe (see Grasso & Rubinstein 2001 for a review).…”

Section: The Origin Of Magnetic Fieldsmentioning

confidence: 99%

Milestones in the Observations of Cosmic Magnetic Fields

Han

Wielebinski

2002

Chin. J. Astron. Astrophys.

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Magnetic fields are observed everywhere in the universe. In this review, we concentrate on the observational aspects of the magnetic fields of Galactic and extragalactic objects. Readers can follow the milestones in the observations of cosmic magnetic fields obtained from the most important tracers of magnetic fields, namely, the star-light polarization, the Zeeman effect, the rotation measures (RMs, hereafter) of extragalactic radio sources, the pulsar RMs, radio polarization observations, as well as the newly implemented sub-mm and mm polarization capabilities. The magnetic field of the Galaxy was first discovered in 1949 by optical polarization observations. The local magnetic fields within one or two kpc have been well delineated by starlight polarization data. The polarization observations of diffuse Galactic radio background emission in 1962 confirmed unequivocally the existence of a Galactic magnetic field. The bulk of the present information about the magnetic fields in the Galaxy comes from analysis of rotation measures of extragalactic radio sources and pulsars, which can be used to construct the 3-D magnetic field structure in the Galactic halo and Galactic disk. Radio synchrotron spurs in the Galactic center show a poloidal field, and the polarization mapping of dust emission and Zeeman observation in the central molecular zone reveal a toroidal magnetic field parallel to the Galactic plane. For nearby galaxies, both optical polarization and multifrequency radio polarization data clearly show the large-scale magnetic field following the spiral arms or dust lanes. For more distant objects, radio polarization is the only approach available to show the magnetic fields in the jets or lobes of radio galaxies or quasars. Clusters of galaxies also contain widely distributed magnetic fields, which are reflected by radio halos or the RM distribution of background objects. The intergalactic space could have been magnetized by outflows or galactic superwinds even in the early universe. The Zeeman effect and polarization of sub-mm and mm emission can be used for the study of magnetic fields in some Galactic molecular clouds but it is observed only at high intensity. Both approaches together can clearly show the role that magnetic fields play in star formation and cloud structure, which in principle would be analogous to galaxy formation from protogalactic clouds. The origin of the cosmic magnetic fields is an active field of research. A primordial magnetic field has not been as yet directly detected, but its ⋆

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Thermal generation of cosmological seed magnetic fields in ionization fronts

Cited by 110 publications

References 0 publications

Cosmological magnetogenesis driven by radiation pressure

Cosmological magnetogenesis driven by radiation pressure

Magnetic Field Generation from Cosmological Perturbations

Milestones in the Observations of Cosmic Magnetic Fields

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