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HINODE Operation Plan (HOP)

accepted on

20-nov-08


 HOP No.

 HOP title

HOP 0095

A statistical analysis of the Magnetic fields of the Network Bright Points (NBP) with the BFI and NFI at the boundaries of supergranules

plan term

2008/12/09-2008/12/10
2009/02/07-2009/02/07
2009/09/06-2009/09/06

@ @

proposer

 name : Malherbe @  e-mail : jean-marie.malherbe[at]obspm.fr

contact person in HINODE team

 name : Berger @  e-mail : berger[at]lmsal.com

 abstract of observational proposal
The physics of intense magnetic flux tubes, which appear in intergranular lanes and mainly at supergranule boundaries as bright points (NBPs) is a very active research topic. Hinode can do a lot on this domain at high spatial resolution.

Flux tubes may be studied individually at high precision using the vector magnetograph of the SOT. This has already been tempted with Hinode by some observers.

Here we suggest an alternative approach in order to have a larger amount of NBPs in the field of view, containing several mesogranules, and probably parts of supergranules, based on BFI and NFI observations. Of course, the accuracy of magnetic field determinations will not be so good, but the number of NBPs in the FOV will be much larger.

The BFI will provide images in the G band. On such images, NBPs appear as proxies of intense magnetic flux tubes.

The NFI will provide the full Stokes IQUV in one of the wings of FeI 5250.2 A (high Lande factor g = 3), or in the line center.

The line of sight magnetic field as well as the transverse magnetic field and orientation (modulo 180) may be deduced under some assumptions (in the frame of theoretical weak fields).

A short sequence of 1 hour in the wing and at line center is sufficient to make a good analysis over NPBs available in the FOV, mainly at the boundaries of supergranules. We do not really know, for transverse magnetic fields (U and Q), if the best sensitivity will be achieved at line center or in the wing (V observations must be performed in the wing).

 request to SOT
Program #1 - NBP Study:
Sequence 1, One hour, pointing: (0,0), disk center tracking

G-Band, 2K x 2K, binning 2 x 2

FG FeI 5250.2, g = 3, IQUV mode, 1.4K x 1.4K, binning 2 x 2, line  
CENTER tuning

Time step 1 min


Sequence 2, One hour, pointing: (0,0), disk center tracking

G-Band, 2K x 2K, binning 2 x 2

FG FeI 5250.2, g = 3, IQUV mode, 1.4K x 1.4K, binning 2 x 2, line WING  
tuning

Time step 1 min

---------------------------------------------------

Program #2 - Supergranular Cell Boundary
Target: Supergranular cell boundary in quiet Sun.

Sequence 1: duration 1 hour

Temporal resolution: 1 minute
FOV: small enough to achieve 1 minute cadence (try 1k x 1k, 2x2 summed to begin...)

- BFI: G-band
- NFI: Na Id in IV mode, standard blue wing tuning


Sequence 2: duration 1 hour

Temporal resolution: 1 minute
FOV: small enough to achieve 1 minute cadence

- BFI: G-band
- NFI: Mg Ib in IV mode standard blue wing tuning


Sequence 3: duration 1 hour
FOV: small enough to achieve 1 minute cadence

- BFI: G-band
- NFI: Mg Ib in shuttered IQUV mode (or only IQU), filter tuned to line CENTER

---------------------------------------------------

Program #3 - Network Wave Propagation
Sequence 1, Six hours, pointing: (0,0), disk center tracking (center on time range)

- FG NFI: FeI 5576 lambda scan, 7 position, 40 mA step, 1K x 1K (or as large as possible to achieve cadence), 1x1

Time step 30 sec

Note: 5576 line scan should be measured first and wavelengths adjusted for line center.

 request to XRT

 request to EIS

 other participating instruments

 remarks
SOT-only

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