학술논문
Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas
Document Type
Working Paper
Author
Meinecke, J.; Tzeferacos, P.; Ross, J. S.; Bott, A. F. A.; Feister, S.; Park, H. -S.; Bell, A. R.; Blandford, R.; Berger, R. L.; Bingham, R.; Casner, A.; Chen, L. E.; Foster, J.; Froula, D. H.; Goyon, C.; Kalantar, D.; Koenig, M.; Lahmann, B.; Li, C. -K.; Lu, Y.; Palmer, C. A. J.; Petrasso, R.; Poole, H.; Remington, B.; Reville, B.; Reyes, A.; Rigby, A.; Ryu, D.; Swadling, G.; Zylstra, A.; Miniati, F.; Sarkar, S.; Schekochihin, A. A.; Lamb, D. Q.; Gregori, G.
Source
Sci. Adv. 8, eabj6799 (2022)
Subject
Language
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}.