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This Week at Physics

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Event Number 4637

  Monday, October 16th, 2017

Plasma Physics (Physics/ECE/NE 922) Seminar
Cosmic Ray Dynamics in Galaxies and Galaxy Clusters
Time: 12:00 pm
Place: Chamberlin 2241
Speaker: Dr. Joshua Wiener, UW Madison
Abstract: Cosmic rays (CRs) make up an important piece of many types of astronomical objects. Though few in number, they can collectively contain as much energy as the thermal gas in galaxies and galaxy clusters. It is therefore important to correctly model the transport of CRs in bulk in order to more completely understand the general dynamics of these systems. I will briefly describe a simple CR transport model where the bulk flow of CRs is limited by the streaming instability. I will then apply this model to a number of systems of different scales: in galaxy clusters, CRs are responsible for synchrotron emission seen as giant radio haloes. In galaxies, CRs may be effective drivers of massive outflows, playing a role in stellar feedback and regulation of star formation. On smaller scales, a CR-driven wind which is incident upon a cold dense cloud may be subject to a peculiar bottleneck effect, which may impart significant momentum to the cloud as well as thicken its interface with the surrounding hot gas.
Host: Stanislav Boldyrev
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