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The small-scale dynamo in the low-Mach number regime

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dc.contributor.advisor Banerjee, Robi en_US
dc.contributor.advisor Federrath, Christoph en_US
dc.contributor.author A. C., RADHIKA en_US
dc.date.accessioned 2020-06-18T06:43:24Z
dc.date.available 2020-06-18T06:43:24Z
dc.date.issued 2020-04 en_US
dc.identifier.uri http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/4757
dc.description.abstract We present the first study on the amplification of magnetic fields by the small-scale turbulent dynamo (SSD) in the highly subsonic regime, with Mach numbers ranging from 10^{−3} to 0.4. We study the properties of the SSD as a function of the nature of turbulent driving, in particular the compressive (curl-free) and the solenoidal (divergence-free) driving. We find that for the lower Mach numbers, the saturation efficiency of the dynamo, (Emag/Ekin)sat, increases as the Mach number decreases. Even in the case when injection of energy is purely through longitudinal forcing modes (or no solenoidal component in the turbulent driving), (Emag/Ekin)sat ∼ 10^{−2} at a Mach number of 10^{−3}. We also find that increasing the solenoidal fraction in the driving field increases the saturation efficiency and the amplification rate of the SSD. We apply our results to magnetic field amplification in the early Universe and predict that a SSD can amplify magnetic fields to & 10^{−16} Gauss on scales of 0.1 pc and & 10^{−13} Gauss on scales of 100 pc. This result can explain the intergalactic magnetic fields inferred from blazer γ-ray observations on these scales. We also apply our findings on the low Mach number SSD to the solar corona and the hot interstellar medium in the galactic corona. en_US
dc.description.sponsorship Australian National University for the Future Research Talent award and the University of Hamburg en_US
dc.language.iso en en_US
dc.subject Magnetohydrodynamics en_US
dc.subject Computational Astrophysics en_US
dc.subject Primordial Magnetic Fields en_US
dc.subject MHD Turbulence en_US
dc.subject 2020 en_US
dc.title The small-scale dynamo in the low-Mach number regime en_US
dc.type Thesis en_US
dc.type.degree BS-MS en_US
dc.contributor.department Dept. of Physics en_US
dc.contributor.registration 20151124 en_US


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  • MS THESES [1705]
    Thesis submitted to IISER Pune in partial fulfilment of the requirements for the BS-MS Dual Degree Programme/MSc. Programme/MS-Exit Programme

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