GENERATION OF A SEED MAGNETIC FIELD AROUND FIRST STARS: THE BIERMANN BATTERY EFFECT

Abstract A large number of galaxies have large-scale magnetic fields which are usually measured by the Faraday rotation of radio waves. Their origin is usually connected with the dynamo mechanism which is based on differential rotation of the interstellar medium and alpha-effect characterizing the helicity of the small-scale motions. However, it is necessary to have initial magnetic field which cannot be generated by the dynamo. One of the possible mechanisms is connected with the Biermann battery which acts because of different masses of protons and electrons passing from the central object. They produce circular currents which induce the vertical magnetic field. As for this field we can obtain the integral equation which can be solved by simulated annealing method which is widely used in different branches of mathematics

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Electron energization during merging of self-magnetized, high-beta, laser-produced plasmas

Journal of Plasma Physics ◽

10.1017/s0022377821000787 ◽

2021 ◽

Vol 87 (4) ◽

Author(s):

G. Fiksel ◽

W. Fox ◽

M.J. Rosenberg ◽

D.B. Schaeffer ◽

J. Matteucci ◽

...

Keyword(s):

Magnetic Field ◽

Electron Energy ◽

Intense Laser ◽

Energy Spectra ◽

Laser Beams ◽

Magnetized Plasmas ◽

Plasma Plumes ◽

Biermann Battery ◽

High Beta

Electron energization during merging of magnetized plasmas is studied using the OMEGA and OMEGA EP laser facilities by colliding two plasma plumes, each containing a Biermann-battery self-generated magnetic field. Two neighbouring plasma plumes are produced by intense laser beams, and the anti-parallel Biermann fields merge and reconnect in the process of the plumes’ expansion and collision. To isolate the merging as an acceleration source, the electron energy spectra obtained from two-plume collision shots are compared with the spectra from single-plume shots. Single-plume shots exhibit an energized electron tail with energies up to ${\sim }250\ \textrm {keV}$ . The electrons in merging experiments are additionally accelerated by ${\sim }50\text {--}100$ keV compared to single-plume shots.

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Generation of Seed Magnetic Field around First Stars

10.1063/1.3455916 ◽

2010 ◽

Author(s):

Masashi Ando ◽

Kentaro Doi ◽

Hajime Susa ◽

Marcel Arnould ◽

...

Keyword(s):

Magnetic Field ◽

First Stars

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GENERATION OF SEED MAGNETIC FIELD AROUND FIRST STARS: EFFECTS OF RADIATION FORCE

The Astrophysical Journal ◽

10.1088/0004-637x/716/2/1566 ◽

2010 ◽

Vol 716 (2) ◽

pp. 1566-1572 ◽

Cited By ~ 22

Author(s):

Masashi Ando ◽

Kentaro Doi ◽

Hajime Susa

Keyword(s):

Magnetic Field ◽

Radiation Force ◽

First Stars ◽

Effects Of Radiation

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Magnetic field generation from primordial black hole distributions

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab729 ◽

2021 ◽

Author(s):

I J Araya ◽

M E Rubio ◽

M San Martín ◽

F A Stasyszyn ◽

N D Padilla ◽

...

Keyword(s):

Magnetic Field ◽

Black Hole ◽

Magnetic Monopoles ◽

Primordial Black Hole ◽

Magnetic Field Generation ◽

Field Generation ◽

Seed Field ◽

Field Fluctuations ◽

Biermann Battery ◽

Generation Mechanisms

Abstract We introduce a statistical method for estimating magnetic field fluctuations generated from primordial black hole (PBH) populations. To that end, we consider monochromatic and extended Press-Schechter PBH mass functions, such that each constituent is capable of producing its own magnetic field due to some given physical mechanism. Assuming linear correlation between magnetic field fluctuations and matter over-densities, our estimates depend on the mass function, the physical field generation mechanism by each PBH constituent, and the characteristic PBH separation. After computing the power spectrum of magnetic field fluctuations, we apply our formalism to study the plausibility that two particular field generation mechanisms could have given rise to the expected seed fields according to current observational constraints. The first mechanism is the Biermann battery and the second one is due to the accretion of magnetic monopoles at PBH formation, constituting magnetic PBHs. Our results show that, for monochromatic distributions, it does not seem to be possible to generate sufficiently intense seed fields in any of the two field generation mechanisms. For extended distributions, it is also not possible to generate the required seed field by only assuming a Biermann battery mechanism. In fact, we report an average seed field by this mechanism of about 10−47 G, at z = 20. For the case of magnetic monopoles we instead assume that the seed values from the literature are achieved and calculate the necessary number density of monopoles. In this case we obtain values that are below the upper limits from current constraints.

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Magnetic field amplification in accretion discs around the first stars: implications for the primordial IMF

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab531 ◽

2021 ◽

Vol 503 (2) ◽

pp. 2014-2032

Author(s):

Piyush Sharda ◽

Christoph Federrath ◽

Mark R Krumholz ◽

Dominik R G Schleicher

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Field Strength ◽

Large Scale ◽

Initial Mass Function ◽

Accretion Discs ◽

Small Scale ◽

Dynamo Action ◽

Initial Field ◽

First Stars

ABSTRACT Magnetic fields play an important role in the dynamics of present-day molecular clouds. Recent work has shown that magnetic fields are equally important for primordial clouds, which form the first stars in the Universe. While the primordial magnetic field strength on cosmic scales is largely unconstrained, theoretical models strongly suggest that a weak seed field existed in the early Universe. We study how the amplification of such a weak field can influence the evolution of accretion discs around first stars, and thus affect the primordial initial mass function (IMF). We perform a suite of 3D ideal magneto-hydrodynamic simulations with different initial field strengths and numerical resolutions. We find that, in simulations with sufficient spatial resolution to resolve the Jeans scale during the collapse, even initially weak magnetic fields grow exponentially to become dynamically important due to both the so-called small-scale turbulent dynamo and the large-scale mean-field dynamo. Capturing the small-scale dynamo action depends primarily on how well we resolve the Jeans length, while capturing the large-scale dynamo depends on the Jeans resolution as well as the maximum absolute resolution. Provided enough resolution, we find that fragmentation does not depend strongly on the initial field strength, because even weak fields grow to become strong. However, fragmentation in runs with magnetic fields differs significantly from those without magnetic fields. We conclude that the development of dynamically strong magnetic fields during the formation of the first stars is likely inevitable, and that these fields had a significant impact on the primordial IMF.

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Magnetic-field strengths from optical polarization data

Symposium - International Astronomical Union ◽

10.1017/s0074180900101263 ◽

1967 ◽

Vol 31 ◽

pp. 381-383

Author(s):

J. M. Greenberg

Keyword(s):

Magnetic Field ◽

Optical Polarization ◽

Polarization Data ◽

Term Model ◽

Source Of Information ◽

Field Strengths

Van de Hulst (Paper 64, Table 1) has marked optical polarization as a questionable or marginal source of information concerning magnetic field strengths. Rather than arguing about this–I should rate this method asq+-, or quarrelling about the term ‘model-sensitive results’, I wish to stress the historical point that as recently as two years ago there were still some who questioned that optical polarization was definitely due to magnetically-oriented interstellar particles.

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Observing the galactic magnetic field

Symposium - International Astronomical Union ◽

10.1017/s0074180900101251 ◽

1967 ◽

Vol 31 ◽

pp. 375-380

Author(s):

H. C. van de Hulst

Keyword(s):

Magnetic Field ◽

Fair Agreement ◽

Solar Neighbourhood ◽

Galactic Magnetic Field ◽

The Magnetic Field

Various methods of observing the galactic magnetic field are reviewed, and their results summarized. There is fair agreement about the direction of the magnetic field in the solar neighbourhood:l= 50° to 80°; the strength of the field in the disk is of the order of 10-5gauss.

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