1. Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas
- Author
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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., and Gregori, G.
- Subjects
Physics - Plasma Physics ,Astrophysics - High Energy Astrophysical Phenomena - 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}.
- Published
- 2021
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