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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-8214
DTSTART:20230228T200000Z
DURATION:PT1H0M0S
DTSTAMP:20260414T121517Z
LAST-MODIFIED:20230224T153206Z
LOCATION:Join Zoom Meeting https://berkeley.zoom.us/j/91230714547  Mee
 ting ID: 912 3071 4547
SUMMARY:Reacceleration of Galactic Cosmic Rays Beyond the Knee at the 
 Termination Shock of a Cosmic-Ray-Driven Galactic Wind\, Network in Ne
 utrinos\, Nuclear Astrophysics\, and Symmetries (N3AS) Seminar\, Payel
  Mukhopadhyay \, UC-Berkeley
DESCRIPTION:The origin of cosmic rays above the knee in the spectrum i
 s an unsolved problem. We present a wind model in which interstellar g
 as flows along a non-rotating\, expanding flux tube with a changing sp
 eed and cross-sectional area. Cosmic rays from Galactic sources\, such
  as supernova remnants\, which are coupled to the plasma via Alfvén w
 aves\, provide the main pressure source for driving this outflow. Thes
 e cosmic rays are then subject to diffusive shock reacceleration at th
 e Galactic wind termination shock\, which is located at a distance ~20
 0 kpc. Some of the highest-energy reaccelerated particles propagate up
 stream against the wind and can contribute to the PeV-EeV range of the
  spectrum. We analyze the conditions under which efficient reaccelerat
 ion can occur and find that rigidities ~10-40 PV can be obtained and t
 hat the termination shock may account for half of the proton spectrum 
 measured in IceCube/IceTop experiment. The highest-energy particles th
 at escape downstream from our termination shock\, and similar shocks s
 urrounding most galaxies\, can be further accelerated by intergalactic
  shock fronts.
URL:https://www.physics.wisc.edu/events/?id=8214
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