Small-scale Dynamo in Supernova-driven Interstellar Turbulence

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-04
Major/Subject
Mcode
Degree programme
Language
en
Pages
8
Series
Astrophysical Journal Letters, Volume 910, issue 2
Abstract
Magnetic fields grow quickly even at early cosmological times, suggesting the action of a small-scale dynamo (SSD) in the interstellar medium of galaxies. Many studies have focused on idealized turbulent driving of the SSD. Here we simulate more realistic supernova-driven turbulence to determine whether it can drive an SSD. Magnetic field growth occurring in our models appears inconsistent with simple tangling of magnetic fields, but consistent with SSD action, reproducing and confirming models by Balsara et al. that did not include physical resistivity η. We vary η, as well as the numerical resolution and supernova rate, to delineate the regime in which an SSD occurs. For a given we find convergence for SSD growth rate with resolution of a parsec. For, with the solar neighborhood rate, the critical resistivity below which an SSD occurs is, and this increases with the supernova rate. Across the modeled range of 0.5-4 pc resolution we find that for the SSD saturates at about 5% of kinetic energy equipartition, independent of growth rate. In the range growth rate increases with SSDs in the supernova-driven interstellar medium commonly exhibit erratic growth.
Description
| openaire: EC/H2020/818665/EU//UniSDyn
Keywords
Astrophysical fluid dynamics, Magnetohydrodynamical simulations, Supernova dynamics, Interstellar medium, Interstellar magnetic fields, Supernova remnants, Magnetohydrodynamics, 101, 1966, 1664, 847, 845, 1667, 1964, Astrophysics - Astrophysics of Galaxies
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Citation
Gent, F A, Mac Low, M-M, Käpylä, M J & Singh, N K 2021, ' Small-scale Dynamo in Supernova-driven Interstellar Turbulence ', Astrophysical Journal Letters, vol. 910, no. 2, 15 . https://doi.org/10.3847/2041-8213/abed59