Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas

Abstract

Galaxy clusters are filled with hot, diffuse X-ray emitting plasma, with a stochastically tangled magnetic field whose energy is close to equipartition with the energy of the turbulent motions \cite{zweibel1997, Vacca}. In the cluster cores, the temperatures remain anomalously high compared to what might be expected considering that the radiative cooling time is short relative to the Hubble time \cite{cowie1977,fabian1994}. While feedback from the central active galactic nuclei (AGN) \cite{fabian2012,birzan2012,churazov2000} is believed to provide most of the heating, there has been a long debate as to whether conduction of heat from the bulk to the core can help the core to reach the observed temperatures \cite{narayan2001,ruszkowski2002,kunz2011}, given the presence of tangled magnetic fields. Interestingly, evidence of very sharp temperature gradients in structures like cold fronts implies a high degree of suppression of thermal conduction \cite{markevitch2007}. To address the problem of thermal conduction in a magnetized and turbulent plasma, we have created a replica of such a system in a laser laboratory experiment. Our data show a reduction of local heat transport by two orders of magnitude or more, leading to strong temperature variations on small spatial scales, as is seen in cluster plasmas \cite{markevitch2003}.

References in corpus (5)

• Shocks and cold fronts in galaxy clusters
• Suppression of electron thermal conduction by whistler turbulence in a sustained thermal gradient
• Time-resolved fast turbulent dynamo in a laser plasma
• Experimental demonstration of an inertial collimation mechanism in nested outflows
• Mega-Gauss Plasma Jet Creation Using a Ring of Laser Beams

Cited by in corpus (8)

• Core-collapse supernova inside the core of a young massive star cluster: 3D MHD simulations
• Insensitivity of a turbulent laser-plasma dynamo to initial conditions
• Simulations of Weakly Magnetized Turbulent Mixing Layers
• Effect of non-local transport of hot electrons on the laser-target ablation
• Impact of Electron Transport Models on Capillary Discharge Plasmas
• Collisional whistler instability and electron temperature staircase in inhomogeneous plasma
• Constraints on thermal conductivity in the merging cluster Abell 2146
• Transport of electrons in tangled magnetic fields