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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-3774
DTSTART:20151005T170000Z
DTEND:20151005T180000Z
DTSTAMP:20260305T235130Z
LAST-MODIFIED:20150922T142031Z
LOCATION:2241 Physics Bldg 
SUMMARY:Turbulence Dynamo and Origin of Magnetic Fields in Galaxy Clus
 ters.\, Plasma Physics (Physics/ECE/NE 922) Seminar\, Professor Jungye
 on Cho\, Chungnam National University\, Korea
DESCRIPTION:In usual astrophysical circumstances\, magnetic diffusivit
 y is very low and\, as a result\, magnetic fields lines are tied to fl
 uid elements. Therefore random turbulence motions can efficiently stre
 tch magnetic field lines\, which results in amplification of magnetic 
 field. This turbulence dynamo is believed to play important roles in t
 he origin of cosmic magnetism. For turbulence dynamo\, a weak seed mag
 netic field is required. If the seed field has a primordial origin\, i
 t could be regarded as uniform (or homogeneous) at the scale of galaxy
  clusters. On the other hand\, if the seed field is ejected from an as
 trophysical body\, it could be highly localized in space at the beginn
 ing. In this talk I'll discuss growth of uniform and localized seed ma
 gnetic fields in turbulence. I will demonstrate that growth of both un
 iform and localized seed magnetic fields in clusters of galaxies is ve
 ry similar. Therefore\, it is difficult to tell whether or not the see
 d magnetic field has a cosmological or an astrophysical origin in clus
 ters of galaxies. However\, I'll show that it is possible to tell the 
 difference in filaments. I’ll also claim that turbulence dynamo mode
 ls favor an astrophysical origin of cosmic magnetism\, rather than a p
 rimordial origin.
URL:https://www.physics.wisc.edu/events/?id=3774
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