Magnetofluid dynamics of magnetized cosmic plasma: firehose and gyrothermal instabilities

Schekochihin, A. A.; Cowley, S. C.; Rincon, F.; Rosin, Mark

doi:10.1111/j.1365-2966.2010.16493.x

Cited by 81 publications

(135 citation statements)

References 71 publications

(158 reference statements)

Supporting

Mentioning

134

Contrasting

Order By: Relevance

“…In a weakly collisional plasma, Kunz (2011) hasshown that anisotropic viscosity can impair the growth of HBI. Pressure anisotropy can also drive plasma micro-instabilities that trap ions in magnetic field fluctuations tangled on scales of their gyroradii and therefore stifle the heat flux (Schekochihin et al 2010;Kunz et al 2014). However, it is currently unknown whether electrons, which are the main contributors to the conductivity, would be affected by similar plasma instabilities.…”

Section: ( )mentioning

confidence: 99%

Interplay Among Cooling, Agn Feedback, and Anisotropic Conduction in the Cool Cores of Galaxy Clusters

Yang

Reynolds

2016

ApJ

View full text Add to dashboard Cite

Feedback from the active galactic nuclei (AGNs) is one of the most promising heating mechanisms to circumvent the cooling-flow problem in galaxy clusters. However, the role of thermal conduction remains unclear. Previous studies have shown that anisotropic thermal conduction in cluster cool cores (CCs) could drive the heat-flux-driven buoyancy instabilities (HBIs) that reorient the field lines in the azimuthal directions and isolate the cores from conductive heating from the outskirts. However, how the AGN interacts with the HBI is still unknown. To understand these interwined processes, we perform the first 3D magnetohydrodynamic simulations of isolated CC clusters that include anisotropic conduction, radiative cooling, and AGN feedback. We find the following: (1) For realistic magnetic field strengths in clusters, magnetic tension can suppress a significant portion of HBI-unstable modes, and thus the HBI is either completely inhibited or significantly impaired, depending on the unknown magnetic field coherence length. (2) Turbulence driven by AGN jets can effectively randomize magnetic field lines and sustain conductivity at ∼1/3 of the Spitzer value; however, the AGN-driven turbulence is not volumefilling. (3) Conductive heating within the cores could contribute to ∼10% of the radiative losses in Perseus-like clusters and up to ∼50% for clusters twice the mass of Perseus. (4) Thermal conduction has various impacts on the AGN activity and intracluster medium properties for the hottest clusters, which may be searched by future observations to constrain the level of conductivity in clusters. The distribution of cold gas and the implications are also discussed.

show abstract

Section: ( )mentioning

confidence: 99%

Interplay Among Cooling, Agn Feedback, and Anisotropic Conduction in the Cool Cores of Galaxy Clusters

Yang

Reynolds

2016

ApJ

View full text Add to dashboard Cite

show abstract

“…As derived in Schekochihin et al (2010), an exact equation for the electron pressure tensor P e reads, when neglecting collisions,…”

Section: Appendix a Nongyrotropic Electron Pressure Tensormentioning

confidence: 99%

Electron-scale reduced fluid models with gyroviscous effects

2017

View full text Add to dashboard Cite

Reduced fluid models for collisionless plasmas including electron inertia and finite Larmor radius corrections are derived for scales ranging from the ion to the electron gyroradii. Based either on pressure balance or on the incompressibility of the electron fluid, they respectively capture kinetic Alfvén waves (KAWs) or whistler waves (WWs), and can provide suitable tools for reconnection and turbulence studies. Both isothermal regimes and Landau fluid closures permitting anisotropic pressure fluctuations are considered. For small values of the electron beta parameter β e , a perturbative computation of the gyroviscous force valid at scales comparable to the electron inertial length is performed at order O(β e ), which requires second-order contributions in a scale expansion. Comparisons with kinetic theory are performed in the linear regime. The spectrum of transverse magnetic fluctuations for strong and weak turbulence energy cascades is also phenomenologically predicted for both types of waves. In the case of moderate ion to electron temperature ratio, a new regime of KAW turbulence at scales smaller than the electron inertial length is obtained, where the magnetic energy spectrum decays like k −13/3 ⊥ , thus faster than the k −11/3 ⊥ spectrum of WW turbulence.

show abstract

“…Large suppression factors thus suggest a short coherence length (<kpc), which may be a simple byproduct of highly chaotic turbulent motions in the ICM. On top of that, plasma microinstabilities (e.g., firehose, Schekochihin et al 2010) acting on scales λ e may drastically change the transport properties, leading to further suppression (McNamara & Nulsen 2012). Simulating the kpc region and the gyroradius scales (for a μG field in a 10 8 K plasma, the gyroradius is 10 −10 pc!)…”

Section: Thermal Conduction In the Local Icmmentioning

confidence: 99%

The stripping of a galaxy group diving into the massive cluster A2142

Eckert

Molendi

Owers

et al. 2014

A&A

105

View full text Add to dashboard Cite

Structure formation in the current Universe operates through the accretion of group-scale systems onto massive clusters. The detection and study of such accreting systems is crucial to understand the build-up of the most massive virialized structures we see today. We report the discovery with XMM-Newton of an irregular X-ray substructure in the outskirts of the massive galaxy cluster Abell 2142. The tip of the X-ray emission coincides with a concentration of galaxies. The bulk of the X-ray emission of this substructure appears to be lagging behind the galaxies and extends over a projected scale of at least 800 kpc. The temperature of the gas in this region is 1.4 keV, which is a factor of ∼4 lower than the surrounding medium and is typical of the virialized plasma of a galaxy group with a mass of a few 10 13 M . For this reason, we interpret this structure as a galaxy group in the process of being accreted onto the main dark-matter halo. The X-ray structure trailing behind the group is due to gas stripped from its original dark-matter halo as it moves through the intracluster medium (ICM). This is the longest X-ray trail reported to date. For an infall velocity of ∼1200 km s −1 we estimate that the stripped gas has been surviving in the presence of the hot ICM for at least 600 Myr, which exceeds the Spitzer conduction timescale in the medium by a factor of 400. Such a strong suppression of conductivity is likely related to a tangled magnetic field with small coherence length and to plasma microinstabilities. The long survival time of the low-entropy intragroup medium suggests that the infalling material can eventually settle within the core of the main cluster.

show abstract

Magnetofluid dynamics of magnetized cosmic plasma: firehose and gyrothermal instabilities

Cited by 81 publications

References 71 publications

Interplay Among Cooling, Agn Feedback, and Anisotropic Conduction in the Cool Cores of Galaxy Clusters

Interplay Among Cooling, Agn Feedback, and Anisotropic Conduction in the Cool Cores of Galaxy Clusters

Electron-scale reduced fluid models with gyroviscous effects

The stripping of a galaxy group diving into the massive cluster A2142

Contact Info

Product

Resources

About