Query : 2000A&A...353..108B

2000A&A...353..108B - Astronomy and Astrophysics, volume 353, 108-116 (2000/1-1)

The role of Kelvin-Helmholtz modes in superwinds of primeval galaxies for the magnetization of the intergalactic medium.


Abstract (from CDS):

Superwinds of primeval dwarf galaxies seem to play an important role in the early magnetization of the intergalactic medium. Realistic estimates of the ``ultimate'', post-outflow diffuse intergalactic magnetic field strengths cannot be made with simple flux conservation arguments. Rather one has to consider dynamical field regeneration mechanisms. Furthermore the role of the neutral component of the superwind outflow gas needs to be taken into account since local-universe outflow winds are known to be only partially ionized. Kelvin-Helmholtz instabilities are one plausible candidate for the amplification of magnetic flux expelled from the starbursting primeval galaxies. We examine solutions of the analytically derived generalized dispersion relation that is valid for partially ionized plasmas. Our calculations indicate that Kelvin-Helmholtz modes can operate fast enough to amplify the magnetic field strengths in superwinds within the timescale of the outflow. Plasma-neutral gas simulations show that the non-linear evolution of the Kelvin-Helmholtz modes resemble the pure MHD one and corroborate the idea that the coupling of the neutral and ionized components is sufficient to convert the free energy supplied by the superwinds to magnetic field energy. We argue that further amplification can be expected due to the development of smaller vortices and sharper magnetic field gradients during the continuous injection of magnetic flux.

Abstract Copyright:

Journal keyword(s): galaxies: magnetic fields - galaxies: intergalactic medium - galaxies: dwarf - galaxies: starburst - instabilities - plasmas

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5583 6
2 NGC 3079 Sy2 10 01 57.8789863992 +55 40 47.449758324 11.57 11.54 10.86     ~ 1311 3
3 NGC 4631 GiP 12 42 08.009 +32 32 29.44   9.78 9.19 9.10   ~ 1024 2
4 NGC 4666 GiP 12 45 08.676 -00 27 42.88   11.7   11.5 10.7 ~ 358 1

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