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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-4949
DTSTART:20181119T180500Z
DURATION:PT1H0M0S
DTSTAMP:20260419T075844Z
LAST-MODIFIED:20181107T175812Z
LOCATION:2241 chamberlin hall
SUMMARY:Wave generation and heat flux suppression in astrophysical pla
 sma systems\, Plasma Physics (Physics/ECE/NE 922) Seminar\, Gareth Rob
 erg-Clark \, Univ. Maryland
DESCRIPTION:Heat flux suppression in collisionless plasmas for a large
  range of
\nplasma beta is explored using two-dimensional particle-in-
 cell
\nsimulations with a strong\, sustained thermal gradient. We find
  that a
\ntransition takes place between whistler-dominated (high-beta
 ) and
\ndouble-layer-dominated (low-beta) heat flux suppression. Whist
 lers
\nsaturate at small amplitude in the low beta limit and are unabl
 e to
\neffectively suppress the heat flux. Electrostatic double layers
  suppress
\nthe heat flux to a mostly constant factor of the free stre
 aming value
\nonce this transition happens. The double layer physics i
 s an example of
\nion-electron coupling and occurs on a scale of rough
 ly the electron
\nDebye length. The scaling of ion heating associated 
 with the various
\nheat flux driven instabilities is explored over the
  full range of
\nbeta explored. The range of plasma-betas studied in t
 his work
\nmakes it relevant to the dynamics of a large variety of ast
 rophysical
\nplasmas\, including the intracluster medium of galaxy clu
 sters\, hot
\naccretion flows\, stellar and accretion disk coronae\, a
 nd the solar wind.
URL:https://www.physics.wisc.edu/events/?id=4949
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