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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0059

CORE: Quiet Sun Evolution - A Hinode Heritage Study

plan term


@ @


 name : P. R. Young @  e-mail : P.R.Young[at]rl.ac.uk

contact person in HINODE team

 name : P. R. Young @  e-mail : P.R.Young[at]rl.ac.uk

 abstract of observational proposal
A long, continuous study of the quiet Sun is requested to form a eheritagef data-set that will be suitable for a variety of scientific investigations both for current and future solar researchers.

Through observations obtained over the initial year of Hinode operations, observing sequences have been optimised and instrumental issues characterised, and we are now in a position to make full and effective use of the suite of instruments. While all three instruments are still in excellent health it is imperative that the opportunity be taken to obtain long duration, high quality data-sets that make best use of the Hinode instruments and that will provide a long-term resource for scientists.

Here we request a single, near-uninterrupted observation of a patch of quiet Sun for a period of 72 hours as it crosses the meridian at solar minimum. The emphasis will be on obtaining detailed diagnostics of the quiet Sun with a good-to-modest cadence over the 72 hour period. Science goals that will be addressed from the observation include

. evolution and heating of coronal bright points
. response of the corona to magnetic emergence and cancellation effects
. appearance and disappearance of small-scale coronal holes within the quiet Sun

however the key goal of the observation is to provide a data-set that makes optimum use of each instrument and that will provide an important resource for the whole of the solar physics community.

The output from this HOP will be an archival data-set that is anticipated to very valuable to both current and future researchers: a near continuous 72 hour record of a patch of quiet Sun close to solar minimum. Because of this heritage aspect of the observation, the following special conditions are requested:

. only two XRT synoptics will be performed each day, separated by 12 hours, in order to minimize disruption of the data-set
. no other activities will take place during the 72 hour period, including calibration or engineering activities, except those that are essential daily activities

In addition, a change to the instrument data recorder allocations is requested. EIS will increase to a 23% allocation, and SOT fall to a 62% allocation. The increase for EIS allows a 50% increase in the field of view, thus allowing a greater area of quiet Sun to be observed. The small, 11% decrease in the SOT data recorder allocation is deemed reasonable given that high cadence is not a key requirement of this HOP. This issue is discussed further below.

 request to SOT
Magnetograms are important for identifying magnetic cancellation/emergence events, while G-band and Ca II are important for identifying release at photospheric/chromospheric heights that can be related to the transition region/coronal emission observed with EIS.

NFI Mg I magnetograms should be interspersed with BFI Ca II and G-band images. The BFI focus should be optimised for Ca II.

Time cadence does not need to be high, and both NFI and BFI should have a FOV in X of at least 180h (to match EIS), and have the full field of view in Y.

It is important that a regular and consistent mixing of the three filters should be maintained during the 72 hour observation period to obtain a homogeneous data-set.

 request to XRT
A continuous cycling through at least 5 filters is requested with a modest cadence. Enough filters are required to yield accurate DEM estimates. Field of view must be at least as big as EIS (180hx360h).

 request to EIS
EIS will obtain detailed spectra with > 40 emission lines covering a wide range of temperature over a 180h x 360h spatial area, at a modest cadence of 50 minutes. This is sufficient to capture evolution of structures with lifetimes of a few hours or more. The 2h slit will be used as this enables faster rastering (by a factor 4).

A new EIS study has been created for this HOP. It is a modification of the successful PRY_loop_footpoints and PRY_footpoints_v2 studies which have been run over 500 times during the first year of EIS operations, and which are specially adapted to observing cool plasma. The new study (QS_diagnostics_HI) consists of two rasters that are almost identical, except that the first takes a larger portion of the EIS spectrum. By adjusting the relative number of repeats of the two rasters, the EIS data rate can be optimised.

Information for EIS CO: an observing day should be broken down into approximately four 6 hour blocks. For each block, a slot context study (study acronym: slot_context_raster) should be run once at the start of the block. This should be followed by a single entry of QS_diagnostics_HI. This study consists of two rasters and the number of raster repeats of each should be adjusted to fill the 6 hour time block. The relative number of repeats of the two rasters should be adjusted to optimise the EIS data rate for the observing block (check with D. Williams or D. Brooks for details).

 other participating instruments

Pointing: The pointing should be set to ensure that the observed region crosses Sun centre at the middle point of the 72 hour period.

Duration: The observation should begin at the start of a daily plan, i.e., around 11 UT and finish at the end of the third dayfs plan.

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