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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0147

Formation and Decay of Sunspot Penumbrae

plan term


@ @


 name : Choudhary, Deng, Penn @  e-mail : debiprasad.choudhary[at]csun.edu

contact person in HINODE team

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

 abstract of observational proposal
Introduction: The decay of sunspot penumbrae as part of active region evolution is an important topic related to flow fields in and around sunspots. Measurements of horizontal proper motions in sunspot penumbrae show a distinct divergence line in the middle of the penumbra. The observed outward motion in the outer penumbra is related to the Evershed flow and moving magnetic features (MMFs), which migrate to the sunspot moat. Deng et al. (2007) provided a high-resolution study of a decaying sunspot using two-dimensional spectroscopy, which showed that this divergence line still existed even after the sunspot decayed to a pore, i.e., the moat flow was still detectable. MMFs have a distinct height dependence (Choudhary and Balasubramniam 2007). In the lower atmosphere, they have a sophisticated magnetic field structure of tight low-level loops, which also show signs of twisted magnetic field lines, whereas higher in the atmosphere, the loop structure is more relaxed and closer to a potential field configuration. These mo-tions of small-scale magnetic features are embedded in the global flow fields of active regions (Choudhary et al. 2002b, Choudhary and Gosain 2003), which are either due to the pressure imbalance in two opposite polarity re-gions know as siphon flow or due to the Coriolis force, while the spots are traveling through the convection zone.  

Primary Objectives: The prime objective of this HOP is to make the imaging and spectropolarimetery observations of sunspot penumbra along with the near IR observations at HeI 1083.0 nm, CaII 854.2 nm and FeI 1.5 µm line, to study the condition of penumbra formation or disappearance and the three dimensional magnetic configuration favorable for penumbral formation.

 request to SOT
We request this HOP be run when a sunspot appears, in order to make coordinated ground based  observations. The ground based observations will be carried out as described in the next section. In this observing sequence we plan to obtain the imaging observations at the disk center simultaneously with CaII,  G-band, blue continuum at 450.5 nm along with the narrow-band filters at Na and MgII filters. Na and MgII filters will be used in IQUV mode.
FILTERS:       Ca II H, G-band, continuum filters at 450.45 nm (blue) and 668.4 nm (red).
FOV:            Covering Sunspot
CADENCE:        about 1 minute.      
END TIME:       TBD      
REPETITION:     Repeat to fill the available time slot
XCEN           TBD
YCEN           TBD

FILTERS:        Mgb II if possible. We can also sequentially use other filters such as Na and Halpha.
FOV:            Covering Sunspot
CADENCE:        about 3 minutes.
END TIME:       TBD      
DURATION:      3-4 hrs  

SOT (SP): Sp observations to cover the sunspot.

 request to XRT

 request to EIS

 other participating instruments
New Infrared Array at McMath-Pierce telescope and SOLIS.

Coordination for ground based observations: We have requested the observing time with McMath-Pierce telescope and SOLIS. We expect to get the observing time in both these instruments. The coordinated observations will be carried-out in the following two manner.
(1) SOLIS: The SOLIS is a synoptic instrument that obtains daily full disk magnetogram observations of the sun in FeI 630.2 nm and CaI 854.2 nm lines. In the coordinated observations with Hinode SOT, we would like to focus on the sunspots following the synoptic observations. So, after the observer performs the synoptic observation, the slit of the spectrograph is placed at one end of the active region that is the target of Hinode SOT. One raster scan to obtain IQUV in FeI 630.2 nm line is performed in the beginning. After this operation, the spectrograph is tuned to CaI 854.2 nm, region.  Repeated raster scans are taken to build the IQUV data cube time sequence.  

As the Hinode observer informs the PI of this HOP, he will contact the SOLIS manager and observer to request them for performing the SOLIS observations. Generally, these observations are carried-out during 17:00 - 24:00 Hrs UT.

(2) McMath-Pierce near IR observations: We shall have telescope times allocated to us from Januray-March 2010. As soon as we get these dates, we shall inform the Hinode observer. We would request this HOP to run during our near IR observations at McMath-Pierce telescope.  Generally, these observations are carried-out during 17:00 - 24:00 Hrs UT.

MacMath-Pearce telescope time available: 2010 Jan 11-15, Feb 1-5 and Mar 8-12

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