Cosmic Rays in Galaxy Clusters and Their Interaction with Magnetic Fields

Brunetti, G.; Jones, T. W.

doi:10.1007/978-3-662-44625-6_20

Cited by 13 publications

(8 citation statements)

References 206 publications

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“…This regime is of particular interest in both astrophysics and in terrestrial systems where processes on a huge variety of scales are either governed or at least influenced by MHD turbulence. Astrophysical examples include energy transport in the solar convection zone (Canuto & Christensen-Dalsgaard 1998;Miesch 2005), angular momentum transport and energy release in accretion disks (Balbus & Hawley 1998), the core collapse supernova mechanism (Couch & Ott 2015;Mösta et al 2015), the interstellar medium with its starforming molecular clouds (Vázquez-Semadeni 2015;Falgarone et al 2015;Klessen & Glover 2016), and clusters of galaxies that can be used to determine cosmological parameters (Brunetti & Jones 2015;Brüggen & Vazza 2015). In the terrestrial context, this is of interest for a range of plasma experiments, such as laser-produced colliding plasma flows, Z-pinches, and tokamaks (see, e.g., Tzeferacos et al 2018;Haines 2011;Mazzucato et al 2009;Ren et al 2013).…”

Section: Introductionmentioning

confidence: 99%

As a matter of tension -- kinetic energy spectra in MHD turbulence

Grete,

O'Shea,

Beckwith

2020

Preprint

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Magnetized turbulence is ubiquitous in many astrophysical and terrestrial systems but no complete, uncontested theory even in the simplest form, magnetohydrodynamics (MHD), exists. Many theories and phenomenologies focus on the joint (kinetic and magnetic) energy fluxes and spectra. We highlight the importance of treating kinetic and magnetic energies separately to shed light on MHD turbulence dynamics. We conduct an implicit large eddy simulation of subsonic, super-Alfvénic MHD turbulence and analyze the scale-wise energy transfer over time. Our key finding is that the kinetic energy spectrum develops a scaling of approximately k −4/3 in the stationary regime as the kinetic energy cascade is suppressed by magnetic tension. This motivates a reevaluation of existing MHD turbulence theories with respect to a more differentiated modeling of the energy fluxes.

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Section: Introductionmentioning

confidence: 99%

As a matter of tension -- kinetic energy spectra in MHD turbulence

Grete,

O'Shea,

Beckwith

2020

Preprint

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“…Moreover, given the large scales involved astrophysical systems are often in a turbulent state (Brandenburg & Lazarian 2013). Compressible MHD turbulence itself is expected to be a major factor in many processes such as magnetic field amplification via the turbulent dynamo (Brandenburg & Subramanian 2005;Tobias et al 2013) and particle acceleration in shock fronts which can eventually be observed as cosmic rays (Brunetti & Jones 2015).…”

Section: Introductionmentioning

confidence: 99%

As a Matter of Force—Systematic Biases in Idealized Turbulence Simulations

Grete

O’Shea

Beckwith

2018

ApJL

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Many astrophysical systems encompass very large dynamical ranges in space and time, which are not accessible by direct numerical simulations. Thus, idealized subvolumes are often used to study smallscale effects including the dynamics of turbulence. These turbulent boxes require an artificial driving in order to mimic energy injection from large-scale processes. In this Letter, we show and quantify how the autocorrelation time of the driving and its normalization systematically change properties of an isothermal compressible magnetohydrodynamic flow in the sub-and supersonic regime and affect astrophysical observations such as Faraday rotation. For example, we find that δ-in-time forcing with a constant energy injection leads to a steeper slope in kinetic energy spectrum and less efficient smallscale dynamo action. In general, we show that shorter autocorrelation times require more power in the acceleration field, which results in more power in compressive modes that weaken the anticorrelation between density and magnetic field strength. Thus, derived observables, such as the line-of-sight magnetic field from rotation measures, are systematically biased by the driving mechanism. We argue that δ-in-time forcing is unrealistic and numerically unresolved, and conclude that special care needs to be taken in interpreting observational results based on the use of idealized simulations.

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“…Our understanding of these has been hampered by insufficient radio data. For example, most of the ~60 known radio haloes [66,67] have been found in clusters detected first at X-ray wavelengths, and our knowledge may be biased by selection effects. Next-generation radio surveys will discover hundreds of diffuse radio haloes and thousands of BT galaxies.…”

Section: Clusters Of Galaxiesmentioning

confidence: 96%

Extragalactic radio continuum surveys and the transformation of radio astronomy

Norris

2017

Nat Astron

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Next-generation radio surveys are about to transform radio astronomy by discovering and studying tens of millions of previously unknown radio sources. These surveys will provide new insights to understand the evolution of galaxies, measuring the evolution of the cosmic star formation rate, and rivalling traditional techniques in the measurement of fundamental cosmological parameters. By observing a new volume of observational parameter space, they are also likely to discover unexpected new phenomena. This review traces the evolution of extragalactic radio continuum surveys from the earliest days of radio astronomy to the present, and identifies the challenges that must be overcome to achieve this transformational change.

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Cosmic Rays in Galaxy Clusters and Their Interaction with Magnetic Fields

Cited by 13 publications

References 206 publications

As a matter of tension -- kinetic energy spectra in MHD turbulence

As a matter of tension -- kinetic energy spectra in MHD turbulence

As a Matter of Force—Systematic Biases in Idealized Turbulence Simulations

Extragalactic radio continuum surveys and the transformation of radio astronomy

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