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xrt_co: - Draft proposal
Attached is a draft proposal for a set of observations designed to
meridional circulation from XBPs. It is a difficult and time
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
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.
Full-disk images: 1024x1024 (2x2 binning, compressed)
Pointing requirements: Near disk center observations every
4 hours for 14 days.
Observations: long and short exposures with a single filter (4 images
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
firstname.lastname@example.org MS 58
Office 617 496 7725 60 Garden Street
Fax 617 496 7577 Cambridge, MA 02138
Cell 508 728 5424 USA