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xrt_co: - Draft proposal

Attached is a draft proposal for a set of observations designed to  
measure the
meridional circulation from XBPs. It is a difficult and time  
consuming task,
so please review and comment on the feasibility and science value. If
we think this is worthwhile I will present it to the SSC in September.


Hinode Operation Plan Request

Title of the proposed research:
Detection of meridional motion/flow in the solar corona using
XBPs as tracers from Hinode/XRT full-disk images

Hinode contact: DeLuca		edeluca[at]cfa.harvard.edu

Edward DeLuca, R. Kariyappa and K. Reeves

Proposed investigations:

It is known from earlier photospheric studies that the polar 
faculae migrate towards poles and give rise to meridional 
circulation and whereas the sunspots will migrate towards 
equator give rise to butterfly diagram.  There are also 
investigations on the meridional motions of small scale 
magnetic features in the photosphere.  

It will be interesting to detect/search for meridional 
motion in the solar corona using XBPs. From a full-disk 
time sequence images, we can examine the XBPs at the lower 
and higher latitudes to clarify whether the XBPs migrate 
towards pole or equator.  From these studies we can bring 
out the differences, if any, in the meridional motions in 
northern and southren hemispheres (asymmetry in meridional 
motion).   Determine the meridional velocity using XBPs 
in the corona and compare with photospheric meridinal 
motions derived from sunspots and faculae.  In addition, 
we can determine the long-term variations in coronal 
meridional motions as a function of solar magnetic 
activity.  The adventage in using XBP as 
tracers is that the XBPs are present through out the 
solar cycle independent of the solar magnetic activity.   
In the case of photosphere, the sunspots and faculae are 
not present during solar minimum, but this is not the 
case in coronal XBPs.  We can also investigate how the 
coronal meridional motion related to the latitude and 
strength of the solar cycle.  These studies will also 
help to understand the role of meridional motion in 
the corona in transporting the fields towards the poles.

The observations require coordination with other 
Hinode observations over a two-week period.

Proposed observations:


Full-disk images: 1024x1024 (2x2 binning, compressed)

Filter: Ti_poly 

Pointing requirements: Near disk center observations every
4 hours for 14 days.

Observations: long and short exposures with a single filter (4 images
per pointing).

Observations may be repeated 4 times per year.

Note: We are looking for long lived XBPs because the meridional
circulation speed is only ~15m/s an XBP that lasts 7 days will
travel 9Mm (~10"), or 5 2x2 binned pixels. These observations
will also produce date useful for other large FOV studies.

       Dr. Edward E. DeLuca           Smithsonian Astrophysical  
       edeluca@cfa.harvard.edu     MS 58
Office 617 496 7725                     60 Garden Street
Fax     617 496 7577                     Cambridge, MA  02138
Cell    508 728 5424                     USA