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HINODE Operation Plan (HOP)

accepted on

29-aug-10


 HOP No.

 HOP title

HOP 0169

Hunt for MHD waves: Magneto-seismology of pores and MBPs

plan term

2010/09/20-2010/09/30

@ @

proposer

 name : Erdelyi, Dorrian, Jess, Mathioudakis, Morton, Taroyan, 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
Introduction
*************

The rapid rise of plasma temperature in the solar atmosphere is still an unresolved problem in plasma-astrophysics. 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. The heating process(es) take(s) place both in active regions (AR) and in the quiet Sun (QS), whatever the latter means. It is likely that a combination of different heating processes operate in ARs and QS, however, it is not at all understood whether the nature of these heating processes is the same or not in the various plasma regions. A feasible common 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 comprehensive tracking MHD waves from photosphere to chromosphere in localised magnetic waveguides with emphases on the magnetic signatures of these waves; (ii) Next, we determine the actual identity and nature of the detected MHD waves (slow, fast, Alfven; kink, sausage; surface, body; etc.); (iii) By means of novel magneto-seismology we will determine not just the morphology of these localised MHD waveguides (potential or not) but will also construct their 3D magnetic mapping and attempt to determine their heating contribution through spatio-magneto seismology.

We plan to carry out these studies in localised magnetic structures called magnetic bright points (MBPs) and small pores. 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 sunspots 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 observational reports on oscillatory phenomena both in MBPs or pores. However, only a limited number of studies have addressed MBP or pore oscillations with recent high-resolution ground and space-based observations. Reports on magnetic oscillations of MBPs or pores are even more limited.

From MHD wave theory perspectives it is strongly anticipated that signatures of the energy transport by magnetic waves through the chromosphere may be detectable in the oscillatory dynamics of QS MBPs and AR pores both in Doppler and Stokes data.

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 about the (i) identity and (ii) degree of magnetic wave coupling from the photosphere to upper chromosphere; (iii) topological 3D magnetic connectivity; and (iv) efficiency of MHD wave energy transport (and dissipation). We plan to use 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 magnetic activity to the TR and corona. Our observing setup will allow us to search for simultaneous magnetic (full Stokes) and Doppler signatures of MHD 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 full Stokes parameters, velocity and/or intensity with frequencies above 2-3 mHz, thus confirming the existence of a range of magnetic waves (longitudinal, kink or Alfven) waves in lower solar atmospheric localised magnetic structures; we expect to detect and discover Alfven waves in AR pores in Stokes parameters!; (ii) perform simultaneous spectro-polarimetry of MBPs and pores which will allow us to link the oscillatory signatures in Stokes, velocity and intensity (if any), with the magnetic field topology and field strength within the localised (MBP, pore) waveguide; (iii) estimate the kinetic and magnetic energy flux that can be transmitted by the detected MHD 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 atmosphere.

Unprecedented high spatial resolution observation with SOT Spectro-Polarimeter (SP) aboard Hinode will provide magnetograms in Na D I, Ca II K and if possible H alpha line center and wing emission. SOT will observe the photosphere with SP (6301/6302 A) and with NFI magnetograms (5250.2 A). SP has a very skinny field of view to perform very high cadence of about a 1 min or even less, and Shutter-less NFI magnetograms provide wide-field context Stokes IQUV images at the blue wing with time cadence of about 30 sec. 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

SOT-SP
Fast map, FOV 5"x82" (32 slit pos, 2x2 sum), 30-60s cad (the less the better), 2 side CCDs-> 600Mbit/1H Note: The SP FOV of 5"x82" is ideal. We would start SP observation with a wider FOV (~10Óx82Ó), and confirming the stability of offset between Hinode and DST/ROSA/IBIS through the observation, we would decrease the FOV (cadence). In the core time, SP should run simultaneously as long as the telemetry permits.

 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 6 days (20-25 September 2010), Quiet Sun:

STUDY:           swat_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

Note1: swat_mbps_1 should be preceded by swat_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:           swat_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

Note1: swat_mbps_2qs should be preceded by swat_mbps_3 with 29 step x 2 arcsec scan taken in the same lines for context image purposes. This will take around 5 mins.

Note2: After the last repetition in swat_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 5 days (26-30 September 2010), Active Region:

STUDY:           swat_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

Note1: swat_mbps_1 should be preceded by swat_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:           swat_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

Note1: swat_mbps_2ar should be preceded by swat_mbps_3 with 29 step x 2 arcsec scan taken in the same lines for context image purposes. This will take around 5 mins.

Note2: After the last repetition in swat_mbps_2ar another 29 step x 2 arcsec scan taken in the same lines should be taken for context image purposes (i.e. repeat swat_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.

SDO:
Leon Golub takes care of it.

Sac Peak: Dunn Solar Telescope
********************************
ROSA & IBIS
***********
We propose to use the DST equipped with ROSA & IBIS for 10 days 20-30 September 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 A triplet, upper chromosphere) absorption profiles that are formed in the photosphere and chromosphere, respectively.

Lines for IBIS requested:
1st 6 days (20-25 September 2010): use Na I D (5895.9 A, upper photosphere)
2nd 5 days (26-30 September 2010): 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 February 2010.

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 20-30 September 2010.

POINTING: MBP on 1st 6 days (Quiet Sun).
         AR pore or similar structure (small sunspot) on remaining 5 days.

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

TARGET:
Contact persons: robertus [at] 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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