<The full description>
Initial helioseismology observations with BFI (quiet Sun regions
on January 1 and February 28, and sunspots on January 8 and May 2)
have showed uniqueness and importance of these observations for
helioseismology. These observations allow us to extend the
time-distance helioseismology for much shorter wave travel
distances and probe the subsurface layers in much greater
detail. Also, simultaneous observations in two filters provide
unique information about wave interaction with the atmospheric
layers and magnetic fields, allowing us to obtain more
knowledge about the wave physics and improve the quality
of helioseismic inference. In addition, the SOT FG observations
provide unique capability of measuring flows at high latitudes
and polar regions. Joint observations with SOHO/MDI are particularly
valuable.
However, our analysis of the FG data shows that the solar noise
level in the FG data (G-band, blue continuum and CaII H) is
higher than in the corresponding Dopplergram data. Thus, it
is necessary to have longer time series for the helioseismology
(time-distance) measurements. Our preliminary analysis shows
that the FG data require 12-hour continuous runs with 1-min
cadence for helioseismology analysis.
The SOHO/MDI continuous contact schedule for this year is
the following:
SOHO/MDI Future Continuous Contact Periods:
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(Jul 18-22 2007 MDI Continuous Contact)
Sep 10 - Nov 11 2007 MDI 60-day Continuous Contact
(Dec 26-30 2007 MDI Continuous Contact)
We propose to schedule Hinode helioseismology observations during
these periods, particularly, during the 60-day continuous run.
At the beginning or at the end of this period we propose to schedule
two joint observing runs with MDI data taken in the high-resolution
mode. For the first run, both SOT/FG and MDI data will be taken in
the MDI high-resolution field of view (tracking a quiet Sun region
or a magnetic region). The required minimal length of these
observations is 12 hours. For the second run, we propose to keep MDI
in the hi-res mode and point SOT to a high-latitude regions for
large-distance measurements, which will allow us to reach the
tachocline and estimate the sensitivity of these measurements to
the deep meridional flow. These measurements require 24-hour
continuous run. Such two-point observation can be also made
with MDI in the full-disk mode. These joint observations will
also allow us to measure the subsurface rotation at high-latitudes.
During the 60-day continuous contact, we propose to schedule
observations of active regions at different positions on the disk,
preferably, of the same active region, following its evolution.
These will allow us to investigate the inclined field effect in the
MDI measurements and improve the inferences of the subsurface
structure and flows for evolving active regions. In the case of the
absence of active regions, tracking a quiet Sun region will provide
for investigations of evolution of supergranulation, and, in
particular, the wave-like behavior of supergranulation. Observations
of a plage region will allow us to investigate scattering of
acoustic and surface gravity waves on small-scale magnetic elements,
and develop diagnostics of these elements by helioseismology.
These observations require at least 12-hour long runs.
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