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On the Dynamics of Helium in the Dilute Intracluster Medium
  Nordita Astrophysics seminars

Wednesday 20 May 2015
from 13:30 to 14:15
at 122:026
Speaker : Martin Pessah (Niels Bohr International Academy)
Abstract : Understanding whether Helium can sediment to the core of galaxy clusters is important for a number of problems in cosmology and astrophysics. For example, our ignorance in the distribution of Helium leads to systematic uncertainties in estimating the density and masses of galaxy clusters. All current models addressing this question are one-dimensional, and ignore the fact that the intracluster medium is a dilute, magnetized plasma, which can effectively channel ions and electrons, leading to anisotropic transport of momentum, heat, and particle diffusion. This anisotropy can lead to a wide variety of instabilities, which could be relevant for understanding the dynamics of the heterogeneous medium. I will present the results of recent analytical and numerical studies analyzing a wide spectrum of instabilities, that feed off thermal and composition gradients in a magnetized tenuous plasma, such as the ICM. I will discuss the future prospects of studying the long term evolution of Helium sedimentation in more realistic settings.

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