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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-1075
DTSTART:20080328T210000Z
DURATION:PT1H0M0S
DTSTAMP:20260409T030734Z
LAST-MODIFIED:20080314T195848Z
LOCATION:2241 Chamberlin Hall (coffee at 3:30 pm)
SUMMARY:Particle Acceleration and Explosive Energy Release by the Sun\
 , Physics Department Colloquium\, Bob Lin\, University of California -
  Berkeley
DESCRIPTION:The Sun is the most energetic natural particle accelerator
  in the solar system\, generating ions up to 10s of GeV and electrons 
 to 100s of MeV\, in both large solar flares and fast coronal mass ejec
 tions. Large solar flares are the most powerful explosions in the sola
 r system\,  releasing up to ~1032 ergs in 100-1000 s\, with >~10-50% o
 f this energy in accelerated particles. I will present observations fr
 om the RHESSI (Ramaty High Resolution Solar Spectroscopic Imager) spac
 ecraft of the hard X-ray (HXR)/gamma-ray continuum and gamma-ray line 
 emission produced by the accelerated electrons and ions\, respectively
 \, showing that the process of magnetic reconnection is key for flare 
 energy release and particle acceleration.  I will also present direct 
 in situ space observations showing that magnetic reconnection and rela
 ted particle acceleration also occurs in the Earth's magnetosphere\, a
 t Mars\, in the solar wind\, and\, very likely\, in cosmic explosions.
   These measurements\, together with recent results from laboratory pl
 asma experiments\, theory\, and simulations\, have led to significant 
 progress in understanding these ubiquitous phenomena.
URL:https://www.physics.wisc.edu/events/?id=1075
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