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HINODE Operation Plan (HOP)

accepted on

21-jan-10


 HOP No.

 HOP title

HOP 0152

Magnetoseismology of bright points

plan term

2010/03/08-2010/03/17

@ @

proposer

 name : Erdelyi, Jess, Mathioudakis, Taroyan, Gonzalez, Verth @  e-mail : robertus[at]sheffield.ac.uk

contact person in HINODE team

 name : Culhane @  e-mail : jlc[at]mssl.ucl.ac.uk

 abstract of observational proposal
The rapid rise of plasma temperature up to 1-2 MK from the solar photosphere towards the corona is still an unresolved problem in solar physics. It is clear that the mechanical energy of sub-photospheric motions is transported somehow into the upper solar atmosphere, where it may be dissipated leading to the heating of the ambient plasma. A possible scenario of energy transport is that the convective motions and solar global oscillations may excite magnetohydrodynamic (MHD) waves in the photosphere, which may then propagate through the chromosphere carrying relevant energy into the corona.

Here we propose (i) observing and tracking MHD waves from photosphere to chromosphere in magnetic bright points representing the QS and pores (or small sunspots) representing ARs; (ii) Next, by means of magneto-seismology of bright points and pores, we will determine not just the nature of these important features (potential or not) but will also construct for the first time their 3D magnetic map.

Magnetic bright points (MBPs) and pores are of the order of kG localised concentrations of magnetic flux that show up as bright features in H_alpha. Pores are often associated with plage. A considerable portion of the chromospheric radiation comes from these MBPs in the QS, while the emission associated with pores or small signposts is even more dominant in ARs. These abundant and intense features were long reported and can be considered an analogue to larger sunspots, the feet of complex, well developed ARs.
High resolution images have revealed that the diameter of MBPs are ~ 1Mm in H_alpha, while pores may be slightly larger (few Mm). Beside the morphological and dynamic studies, there are early observationalreports on oscillatory phenomena both in bright points or pores. However, only a limited number of
studies have addressed bright point or pore oscillations with recent high-resolution ground and space-based observations. It is strongly anticipated that signatures of the energy transport by MHD waves through the chromosphere may be detectable in the oscillatory dynamics of QS MBPs and AR pores.

A comprehensive novel observational study of waves and oscillations in MBPs and pores, to the best of our knowledge, is still lacking. An observational campaign could clarify very important details of (i) the degree of magnetic wave coupling from the photosphere to corona; (ii) topological 3D magnetic connectivity; and (iii) efficiency of wave energy dissipation. We plan to use existing Hinode & TRACE sequences, in addition to acquiring high-cadence ROSA & IBIS data (weather permitting).

Primary Objectives: The primary objective of this proposal is not only to study the dynamic activity in the lower solar atmosphere (i.e., identify the driver at photospheric levels) but to trace that activity to the TR and corona. Our observing setup will allow us to search for waves and oscillations in QS MBPs and AR pores, and use these waves by means of magneto-seismology to construct 3D magnetic mapping. Our ROSA/IBIS setup will allow us to (i)identify oscillatory power in velocity and/or intensity with frequencies above 2-3 mHz, thus confirming the existence of Alfvenic waves in MBPs; we expect to detect and discover Alfven waves in AR pores; (ii) perform simultaneous spectro-polarimetry of MBPs and pores which will allow us to link the oscillatory signatures in velocity and intensity (if any), with the magnetic field topology and field strength within the MBP and pore waveguide; (iii) estimate the energy flux that can be transmitted by the detected Alfven waves and oscillations. With XRT and EIS, we will acquire images and spectral data to enable a determination of the flow, temperatures and electron density structure in the upper atmosphere.  SOT will provide magnetograms in Na D I, Ca II K and if possible H alpha line center and wing emission. TRACE will
provide high-cadence observations with the 171 A filter.

 request to SOT
SOT (BFI):

FILTERS:       Ca II H, G-band and Blue continuum
FOV:           120"x100"
CADENCE:       As high cadence as possible. 10 or 15 second would be good. The less the better.    
START TIME:    15:00 UT
END TIME:      18:00 UT
DURATION:      3 hrs        
REPETITION:    Repeat to fill the available time slot
XCEN           TBD (MBP should be in centre)
Rot comp.:     Rotation compensation to be applied i.e. feature tracking
YCEN           TBD (MBP should be in centre)

SOT (NFI):
FILTERS:       Na I D shuttered IV plus H_alpha center and wing(s) if possible
FOV:           220"x164"
CADENCE:       As high cadence as possible. 10 or 15 second would be good. The less the better      
START TIME:    15:00 UT
END TIME:      18:00 UT      
DURATION:      3 hrs  
REPETITION:    Repeat to fill the available time slot
XCEN:          TBD (MBP should be in centre)
YCEN:          TBD (MBP should be in centre)
Rot comp.:     Rotation compensation to be applied i.e. feature tracking

 request to XRT
FILTERS:       Al/Poly, several G-band images for co-alignment
CADENCE:       ~40 s maximum
FOV:           384"x384"
START TIME:    15:00 UT
END TIME:      18:00 UT
DURATION:      3 hrs
XCEN           xcen = xcen(SOT)
YCEN           ycen = ycen(SOT)

 request to EIS
1st: Quiet Sun - 6 days maximum

STUDY:           mbps_1
RASTER DURATION: around 50 sec
STUDY DURATION:  500 sec (raster duration x nr of repeats)
REPETITION:      run study for about 10 times, till the end of time slot
FOV:             8"X152"
START TIME:      15:05 UT
END TIME:        16:25 UT
DURATION:        approx 1.5 hrs
XCEN:            TBD (MBP should be in centre)
YCEN:            TBD (MBP should be in centre)
Rot comp.:       Rotation compensation to be applied i.e. feature tracking

Note 1: mbps_1 should be preceded by mbps_3 with 29 step x 2 arcsec scan taken
in the same lines for context image purposes. This will take around 5 mins.

STUDY:           mbps_2qs
RASTER DURATION: around 50 sec
STUDY DURATION:  500 sec (raster duration x nr of repeats)
REPETITION:      run study for about 10 times, till the end of time slot
FOV:             4"X152"
START TIME:      16:30 UT
END TIME:        17:50 UT
DURATION:        approx 1.5 hrs
XCEN:            TBD (MBP should be in centre)
YCEN:            TBD (MBP should be in centre)
Rot comp.:       Rotation compensation to be applied i.e. feature tracking

Note 1: mbps_2qs should be preceded by mbps_3 with 29 step x 2 arcsec scan taken in the same lines for context image purposes. This will take around 5 mins.

Note 2: After the last repetition in mbps_2qs another 29 step x 2 arcsec scan taken in the same lines should be taken for context image purposes (i.e. repeat mbps_3). This will take around 5 mins.

2nd: Active Region/Pore - 4 days maximum

STUDY:           mbps_1
RASTER DURATION: around 50 sec
STUDY DURATION:  500 sec (raster duration x nr of repeats)
REPETITION:      run study for about 10 times, till the end of time slot
FOV:             8"X152"
START TIME:      15:05 UT
END TIME:        16:25 UT
DURATION:        approx 1.5 hrs
XCEN:            TBD (pore should be in centre)
YCEN:            TBD (pore should be in centre)
Rot comp.:       Rotation compensation to be applied i.e. feature tracking

Note 1: mbps_1 should be preceded by mbps_3 with 29 step x 2 arcsec scan taken in the same lines for context image purposes. This will take around 5 mins.

STUDY:           mbps_2ar
RASTER DURATION: around 50 sec
STUDY DURATION:  500 sec (raster duration x nr of repeats)
REPETITION:      run study for about 10 times, till the end of time slot
FOV:             7"X152"
START TIME:      16:30 UT
END TIME:        17:50 UT
DURATION:        approx 1.5 hrs
XCEN:            TBD (pore should be in centre)
YCEN:            TBD (pore should be in centre)
Rot comp.:       Rotation compensation to be applied i.e. feature tracking

Note 1: mbps_2ar should be preceded by mbps_3 with 29 step x 2 arcsec scan taken in the same lines for context image purposes. This will take around 5 mins.

Note 2: After the last repetition in mbps_2ar another 29 step x 2 arcsec scan taken in the same lines should be taken for context image purposes (i.e. repeat mbps_3). This will take around 5 mins.

 other participating instruments
TRACE:
171 A filter with 1550, 1700, 1600 context images every minute.
Rot. comp.:      Rotation compensation to be applied i.e. feature tracking
START TIME:    15:00 UT
END TIME:      18.00 UT
Target: MBP should be in centre.

Sac Peak: Dunn Solar Telescope
ROSA & IBIS

We propose to use the DST equipped with ROSA & IBIS for 10 days 8-17 March 2010. With the proposed observing setup, we aim to achieve the following:

(a) Scan individual line profiles using IBIS. Each profile scan will last for approximately 8 sec and waves with frequencies as high as 60~mHz will be studied (Nyquist frequency). Lines that may be used include the Na I D (5895.9 A, upper photosphere), Fe I (6302 A low photosphere) ,  Fe~I (7090 A, low photosphere), H_alpha (6563 A mid- to u--re chromosphere) & Ca II (8542 Atriplet, upper chromosphere) absorption profiles that are formed in the photosphere and chromosphere, respectively.

Lines for IBIS requested:
For QS target: use Na I D (5895.9 A, upper photosphere)
For AR/Pore target: use Fe~I (7090 A, low photosphere)

Note, we exclude at this stage (though may swap in emergency):
Fe I (6302 A) as already on ROSA
H_alpha (6563 A) as also already on ROSA.
Ca II (8542 a triplet) as in some aspects it is similar to H_alpha is on ROSA. Further, there is already a Ca line (the H one) on SOT anyway, and we want to reduce duplications.

(b) The IBIS observations will be combined with simultaneous ROSA imaging in
H_alpha, G-band, Ca~II K and blue (4170 A) continuum.

(c) Simultaneous line-of-sight magnetograms will be also be acquired by combining the magnetically-sensitive Fe~I line at 6302.5 A (viewed through the tuneable UBF positioned in the blue wing of the line) with a Wollaston prism, in order to obtain Stokes V l.o.s. magnetic field information. Two ROSA cameras will be used to provide simultaneous measurements of left- and right-hand circularly polarized light. Absolute calibration of ROSA magnetograms is currently underway following a successful observing campaign in October 2009.

IBIS Dopplergrams and ROSA imaging at high spatial and temporal resolution will be essential as it will allow us to disentangle any intensity oscillations that may be associated with kink and/or longitudinal waves modes. Kink waves are only linearly incompressible. Through Doppler and magnetic data Alfven waves are expected to be identified. We will therefore be in a position to diagnose MBPs through seismology.

 remarks
Requested Observing interval: We request observing from 15:00 UT for ~3 hrs each on 8-17 March 2010.

POINTING: MBP: 6 days maximum (Quiet Sun).
         AR pore or similar structure: 4 days maximum (small sunspot).

IMPORTANT REMARK: We will inform the Hinode teams well in advance about local weather conditions.

Contact persons: robertus@sheffield.ac.uk (Robertus Erdelyi, who will be at Sac Peak or Mihalis Mathioudakis <M.Mathioudakis@qub.ac.uk>, tel.: +44-(0)28-90973573

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