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Magnetic-field amplification by turbulence in a relativistic shockpropagating through an inhomogeneous medium
- We perform two-dimensional relativistic magnetohydrodynamic simulations of a mildly relativistic shock propagating through an inhomogeneous medium. We show that the postshock region becomes turbulent owing to preshock density inhomogeneity, and the magnetic field is strongly amplified due to the stretching and folding of field lines in the turbulent velocity field. The amplified magnetic field evolves into a filamentary structure in two-dimensional simulations. The magnetic energy spectrum is flatter than the Kolmogorov spectrum and indicates that a so-called small-scale dynamo is occurring in the postshock region. We also find that the amount of magnetic-field amplification depends on the direction of the mean preshock magnetic field, and the timescale of magnetic-field growth depends on the shock strength.
Author details: | Yosuke Mizuno, Martin PohlORCiDGND, Jacek Niemiec, Bing Zhang, Ken-Ichi Nishikawa, Philip E. Hardee |
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DOI: | https://doi.org/10.1088/0004-637X/726/2/62 |
ISSN: | 0004-637X |
Title of parent work (English): | The astrophysical journal : an international review of spectroscopy and astronomical physics |
Publisher: | IOP Publ. Ltd. |
Place of publishing: | Bristol |
Publication type: | Article |
Language: | English |
Year of first publication: | 2011 |
Publication year: | 2011 |
Release date: | 2017/03/26 |
Tag: | gamma-ray burst: general; magnetohydrodynamics (MHD); methods: numerical; relativistic processes; shock waves; turbulence |
Volume: | 726 |
Issue: | 2 |
Number of pages: | 11 |
Funding institution: | NSF [AST-0506719, AST-0506666, AST-0908010, AST-0908040, AST-0908362]; NASA [NNG05GK73G, NNX07AJ88G, NNX08AG83G, NNX09AT66G, NNX10AD48G]; MNiSW [N N203 393034]; Foundation for Polish Science through the EEA Financial Mechanism; Altix3700 BX2 at YITP in Kyoto University |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
Peer review: | Referiert |