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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0100

CORE: Too: AR engineering test

plan term


@ @


 name : Cirtain, Tarbell, Shimizu @  e-mail : jonathan.w.cirtain[at]nasa.gov

contact person in HINODE team

 name : Cirtain @  e-mail : jonathan.w.cirtain[at]nasa.gov

 abstract of observational proposal
SOT: vector magnetic field measurements in the photosphere and clues to the field orientation in the chromosphere.
XRT: high resolution images showing coronal field geometry at all coronal temperatures
EIS: morphology and temperature of all visible structures within the active region

We would like to request the observations for a Hinode active region coordination demonstration.  In addition, this HOP will obtain valuable data for a test of another sort, namely non-linear force-free field extrapolation to produce credible coronal vector magnetic field estimates from Hinode observations.

Hopeful of increasing frequency of active region targets, we request a short observation to demonstrate coordination between instruments for the upcoming increase in cycle 24 active region targets. This observation has ONE goal: demonstrate the Hinode observatory will produce a scientifically useful dataset that incorporates the power of each instrument for these highly valuable targets of opportunity.  This dataset will be used for another evaluation non-linear force-free field extrapolations of coronal fields.  This was requested by the NLFF group led by Karel Schrijver at LMSAL.  Recent results of the NLFF group using Hinode data can be found in http://arxiv.org/abs/0902.1007.  An excerpt from the abstract of that paper follows.

gNonlinear force-free field (NLFFF) models are thought to be viable tools for investigating the structure, dynamics and evolution of the coronae of solar active regions. In a series of NLFFF modeling studies, we have found that NLFFF models are successful in application to analytic test cases, and relatively successful when applied to numerically constructed Sun-like test cases, but they are less successful in application to real solar data. Different NLFFF models have been found to have markedly different field line configurations and to provide widely varying estimates of the magnetic free energy in the coronal volume, when applied to solar data. NLFFF models require consistent, force- free vector magnetic boundary data. However, vector magnetogram observations sampling the photosphere, which is dynamic and contains significant Lorentz and buoyancy forces, do not satisfy this requirement, thus creating several major problems for force-free coronal modeling efforts. In this article, we discuss NLFFF modeling of NOAA Active Region 10953 using Hinode/SOT-SP, Hinode/XRT, STEREO/SECCHI-EUVI, and SOHO/MDI observations, and in the process illustrate the three such issues we judge to be critical to the success of NLFFF modeling: (1) vector magnetic field data covering larger areas are needed so that more electric currents associated with the full active regions of interest are measured, (2) the modeling algorithms need a way to accommodate the various uncertainties in the boundary data, and (3) a more realistic physical model is needed to approximate the photosphere-to-corona interface in order to better transform the forced photospheric magnetograms into adequate approximations of nearly force-free fields at the base of the corona.h

A small to medium-sized AR close to central meridian is the requested target. It must have sunspots and must not be evolving very rapidly when observed.  Since the NLFF extrapolations require vector measurements of the boundary conditions at every position where field lines from the AR intersect the solar surface, large area coverage is needed.  In addition, since the fields in the photosphere are not completely force-free, any additional observations we can collect to indicate the chromospheric field directions are needed, such as H-alpha images.  XRT and EIS images are needed to show the loop geometry in the corona for comparison with the extrapolations.  TRACE and STEREO EUVI images will also be used if available.

The HOP 100 science team will work together to calibrate, combine and analyze the data.  We will provide the Level 2 measurements, internally coaligned, to the NLFF team and anyone else interested within 2 months of collection of a satisfactory observation.

 request to SOT
SP normal map of entire SOT FOV centered on region, or at least covering all spots and plage of the AR if it is much smaller than the entire FOV; followed by SP fast maps of any surrounding areas in which field lines from the AR connect back to the photosphere.  These can be done using multiple pointings offset from the tracked AR.  At each pointing, use the FG to take low cadence H-alpha line center & wing images for clues to chromospheric field direction and low cadence Na D IV images to show region evolution.  If the AR is not near disk center, low cadence Stokes images in Mb b line center will give some additional information about chromospheric fields.  Periodic G-band images for coalignment are also useful.  The SOT program takes about 6 hours and uses one day's normal telemetry (or a little more).

 request to XRT
Al-poly and Be-thin for XRT with a 384x384 FOV: 1x1 binning and Q80-Q85. The cadence should be <30sec; one g-band every 20 minutes for co-alignment.

 request to EIS
Slot images using: MgVII 278.39 A, FeXII 195.16A  &  FeXIV 274.16A,  FeXVI 262.94A  &  FeXXIII 263.97A using a raster of five 40" raster positions and no space in between slot locations in the raster (appropriate cadence and compression per the team).

 other participating instruments
TRACE should take 195A and 1600/WL images for co-alignment.

The HOP requires a small to medium-sized active region, not evolving too rapidly, at its passage across the central meridian.

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