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VERSION:2.0
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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20090130T000000
DTEND;TZID=Atlantic/Canary:20090130T010000
UID:iactalks-193
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/193
CREATED:2009-01-30T00:00:00+00:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Quiet Sun magnetism and Alfven waves as observed with Hinode
DESCRIPTION:Quiet Sun magnetism and Alfven waves as observed with Hinode\nD
 r. Saku Tsuneta\n\nThe magnetic landscape of the polar region (Tsuneta et 
 al, 2008) is characterized by vertical kilogauss patches with super-equipa
 rtition field strength, a coherence in polarity, lifetimes of 5-15 hr, and
  ubiquitous weaker transient horizontal fields (Lites et al 2008, Ishikawa
  & Tsuneta, 2008, 2009). Polar region in 2007 have abundant vertical f
 ields much stronger than the quiet Sun. Unipolar appearance and disappeara
 nce of the kG vertical patches must be closely related to properties of th
 e horizontal flow field in the polar region. Difference and similarity bet
 ween the quiet sun and the polar region are summarized, and its implicatio
 n for solar dynamo will be discussed.  All the open field lines forming th
 e polar coronal hole essentially originate from such magnetic patches, and
  the fast solar wind would emanate from these vertical flux tubes seen in 
 the photosphere. We conjecture that vertical flux tubes with large expansi
 on around the photospheric-coronal boundary serve as efficient chimneys fo
 r Alfven waves that accelerate the solar wind. Indeed, we discovered propa
 gating Alfven waves (kink mode) with magneto-acoustic waves (sausage mode)
  in the solar photosphere with period of 4-13 minutes with Hinode spectro-
 polarimeter (Fujimura and Tsuneta, 2009). We found that these fluctuations
  are superposition of ascending and descending Alfven waves with almost eq
 ual intensities from the analysis of the phase relationship between transv
 erse magnetic and velocity fluctuations. Aflven waves along flux tubes in 
 the quiet sun appear to be efficiently reflected back probably at photosph
 ere-corona boundary. It would be very interesting to measure possible chan
 ge in the reflectivity of Alfven waves depending on the magnetic environme
 nt. 
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