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A galaxy dynamo by Supernova-driven interstellar turbulence

Published online by Cambridge University Press:  01 November 2008

Oliver Gressel
Affiliation:
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany email: ogressel@aip.de, uziegler@aip.de, elstner@aip.de, gruediger@aip.de
Udo Ziegler
Affiliation:
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany email: ogressel@aip.de, uziegler@aip.de, elstner@aip.de, gruediger@aip.de
Detlef Elstner
Affiliation:
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany email: ogressel@aip.de, uziegler@aip.de, elstner@aip.de, gruediger@aip.de
Günther Rüdiger
Affiliation:
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany email: ogressel@aip.de, uziegler@aip.de, elstner@aip.de, gruediger@aip.de
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Abstract

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Supernovae are the dominant energy source for driving turbulence within the interstellar plasma. Until recently, their effects on magnetic field amplification in disk galaxies remained a matter of speculation. By means of self-consistent simulations of supernova-driven turbulence, we find an exponential amplification of the mean magnetic field on timescales of a few hundred million years. The robustness of the observed fast dynamo is checked at different magnetic Reynolds numbers, and we find sustained dynamo action at moderate Rm. This indicates that the mechanism might indeed be of relevance for the real ISM.

Sensing the flow via passive tracer fields, we infer that SNe produce a turbulent α effect which is consistent with the predictions of quasilinear theory. To lay a foundation for global mean-field models, we aim to explore the scaling of the dynamo tensors with respect to the key parameters of our simulations. Here we give a first account on the variation with the supernova rate.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2009

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