Magnetic field amplification by cosmic ray-driven turbulence – I. Isotropic CR diffusion

Brüggen, M.

doi:10.1093/mnras/stt1566

Cited by 23 publications

(16 citation statements)

References 47 publications

(40 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indications of substantial magnetisation along the filamentary region in the SW sector of the Coma cluster have been reported in Bonafede et al (2013). Finally, it has also been suggested that cosmic-ray particles accelerated at strong shocks can substantially amplify upstream magnetic fields (Drury & Downes 2012;Brüggen 2013).…”

Section: Magnetic Fieldsmentioning

confidence: 89%

“…Here we briefly discuss a few possible variations of the magnetic field models studied above, which we can easily test with existing runs. A possibility suggested in the literature is that cosmic rays accelerated by strong shocks can induce turbulence in the shocks upstream and trigger substantial magnetic field amplification (Drury & Downes 2012;Brüggen 2013). We tested this scenario (labelled HSA) by computing the kinetic energy flux that is expected to be dissipated into CRs based on our shock finder and on the acceleration efficiency by Kang & Ryu (2013).…”

Section: Alternative Scenariosmentioning

confidence: 99%

See 1 more Smart Citation

Forecasts for the detection of the magnetised cosmic web from cosmological simulations

Vazza

Ferrari

Brüggen

et al. 2015

A&A

Self Cite

144

View full text Add to dashboard Cite

The cosmic web contains a large part of the total gas mass in the Universe, but it is difficult to detect at most wavelengths. Synchrotron emission from shock-accelerated electrons may offer the chance of imaging the cosmic web at radio wavelengths. In this work we use 3D cosmological ENZO-magnetohydrodynamic simulations (combined with a post-processing renormalisation of the magnetic field to bracket for missing physical ingredients and resolution effects) to produce models of the radio emission from the cosmic web. In post-processing we study the capabilities of 13 large radio surveys to detect this emission. We find that surveys by LOFAR, SKA1-LOW, and MWA have a chance of detecting the cosmic web, provided that the magnetisation level of the tenuous medium in filaments is of the order of ∼1% of the thermal gas energy.

show abstract

Section: Magnetic Fieldsmentioning

confidence: 89%

Section: Alternative Scenariosmentioning

confidence: 99%

Forecasts for the detection of the magnetised cosmic web from cosmological simulations

Vazza

Ferrari

Brüggen

et al. 2015

A&A

Self Cite

144

View full text Add to dashboard Cite

show abstract

“…Additionally, if CRs can stream at super-Alfvenic speed (an interesting yet very debated scenario, e.g., [58]) then the distribution derived in our approximation might be subject to further smoothing in the radial direction. Moreover, in our work we assumed that CRs and magnetic fields do not directly interact, while more detailed work on CR-driven magnetic field instabilities suggest that this is not the case in small-scale features of the ICM (e.g., [59]). Finally, we also neglect the possible re-acceleration of CR-protons by turbulence (e.g., [8]).…”

Section: Discussionmentioning

confidence: 99%

On the Non-Thermal Energy Content of Cosmic Structures

et al. 2016

View full text Add to dashboard Cite

(1) Background: the budget of non-thermal energy in galaxy clusters is not well constrained, owing to the observational and theoretical difficulties in studying these diluted plasmas on large scales; (2) Method: we use recent cosmological simulations with complex physics in order to connect the emergence of non-thermal energy to the underlying evolution of gas and dark matter; (3) Results: the impact of non-thermal energy (e.g., cosmic rays, magnetic fields and turbulent motions) is found to increase in the outer region of galaxy clusters. Within numerical and theoretical uncertainties, turbulent motions dominate the budget of non-thermal energy in most of the cosmic volume; (4) Conclusion: assessing the distribution non-thermal energy in galaxy clusters is crucial to perform high-precision cosmology in the future. Constraining the level of non-thermal energy in cluster outskirts will improve our understanding of the acceleration of relativistic particles and of the origin of extragalactic magnetic fields.

show abstract

“…On the other hand, several papers have suggested that collisionless shocks can significantly amplify the upstream magnetic field independently of the initial conditions (e.g. Drury & Downes 2012, Brüggen 2013, Caprioli & Spitkovsky 2014b. As an explorative study, we investigated the effect of a minimum magnetisation level to allow for DSA, by limiting the acceleration of cosmic-ray protons to upstream fields Bup > Bmin.…”

Section: Cosmic-ray Protons and γ-Raysmentioning

confidence: 99%

Testing cosmic ray acceleration with radio relics: a high-resolution study using MHD and tracers

Wittor¹,

Vazza²,

Brüggen³

2016

Mon. Not. R. Astron. Soc.

Self Cite

115

View full text Add to dashboard Cite

Weak shocks in the intracluster medium may accelerate cosmic-ray protons and cosmic-ray electrons differently depending on the angle between the upstream magnetic field and the shock normal. In this work, we investigate how shock obliquity affects the production of cosmic rays in high-resolution simulations of galaxy clusters. For this purpose, we performed a magneto-hydrodynamical simulation of a galaxy cluster using the mesh refinement code ENZO. We use Lagrangian tracers to follow the properties of the thermal gas, the cosmic rays and the magnetic fields over time. We tested a number of different acceleration scenarios by varying the obliquity-dependent acceleration efficiencies of protons and electrons, and by examining the resulting hadronic γ-ray and radio emission. We find that the radio emission does not change significantly if only quasi-perpendicular shocks are able to accelerate cosmic-ray electrons. Our analysis suggests that radio emitting electrons found in relics have been typically shocked many times before z = 0. On the other hand, the hadronic γ-ray emission from clusters is found to decrease significantly if only quasi-parallel shocks are allowed to accelerate cosmic-ray protons. This might reduce the tension with the low upper limits on γ-ray emission from clusters set by the Fermi-satellite.

show abstract

Magnetic field amplification by cosmic ray-driven turbulence – I. Isotropic CR diffusion

Cited by 23 publications

References 47 publications

Forecasts for the detection of the magnetised cosmic web from cosmological simulations

Forecasts for the detection of the magnetised cosmic web from cosmological simulations

On the Non-Thermal Energy Content of Cosmic Structures

Testing cosmic ray acceleration with radio relics: a high-resolution study using MHD and tracers

Contact Info

Product

Resources

About