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HINODE Operation Plan (HOP)

accepted on

16-jan-2014

 HOP No.

  HOP title

HOP 0251
Spectropolarimetry of flares

plan term

ToO
2014/03/22-2014/03/31

 　 　

proposer

  name : Dalda, Kleint, Tarbell, Judge, Reardon. 　  e-mail :

contact person in HINODE team

  name : Tarbell 　  e-mail : tarbell[at]lmsal.com

 abstract of observational proposal
OBJECTIVE: To study the behavior of the vector magnetic field and possible changes in thermodynamics parameters of flaring active regions in coordination with our observing run at the Dunn Solar Telescope.

SCIENTIFIC RATIONALE
Our knowledge of the vector magnetic field and thermodynamics during the flare activity has recently improved after several results obtained with IBIS and FIRS in coordination with Hinode-SOT/SP (Judge et al., 2010; Kleint, 2012). However, many questions related with ARs that show flare activity need to be answered: i) how is the topology of the sunspot of the AR modified? ii) what is the evolution of the line-of-sight electric density current and the Lorentz force in the AR? iii) how does the magnetic field interact with the plasma in the chromosphere before, during and after the flare event? iv) if there is a modification both in the topology and the evolution of the AR, does the energy release propagate from the photosphere to the chromosphere or vice versa? (see Figure1) and v) what is the role of the reverse Evershed flow in producing flares in some sunspots? (Kleint & Sainz Dalda, 2013, see Figure 2).

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Figure 1. Left: NOAA AR 11302 observed by IBIS on September 24, 2011. The unusual umbral filaments (marked as 1, 2, and 3) were related with flare activity and chromospheric heating. Right: Brightening in the umbral filaments observed by IBIS in Ca II 8542 A during an M flare. Figures from Kleint & Sainz Dalda (2013)
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The Sun is at the maximum of its activity, meaning such observations are best done now to capture a sufficient number of flares. Thus, we aim to observe several C- and M-class flares and possibly an X-class flare during our observations. Coordinated observation involving Hinode, IBIS and FIRS are ideally suited to investigate the above questions.

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Figure 2. NOAA AR 11302 observed by Hinode/SOT-SP at Fe I 6301 & 6302 A. The unusual penumbral filaments host reversed Evershed flow (in blue), both in the more horizontal component of the penumbra (2nd row) and the more vertical component (1st row). Figure from Kleint & Sainz Dalda, (2013)
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We would like to request coordinated Hinode/IRIS observations during the observing time that we were awarded at the Dunn Solar Telescope (DST) at Sac Peak. Dates: March 22-March 31, 2014. Usual observing time at the DST in UT: 1400-1800.

 request to SOT
We will use HINODE-SOT data to get information about the magnetic field and the dynamics of the chromosphere during the flare event(s). If the telemetry allows, we request a combination of FG and SP observation.  

NFI: Chromospheric magnetograms and Dopplergrams at Mg Ib 5172.7 A, or
       Chromospheric fields at Na I D 5896.0 A. 50" x 80", Sh-less IV.
These should use ROI # 2 shifted down on the CCD by 25 arcseconds to get better image quality.

BFI: Chromospheric intensity filtergram at Ca II H 3968.5 A.

SP: Fast map mode. FOV ~ 160"x164", at least one map for context before and after DST observations. If telemetry permits, for small AR, run repeated fast maps (60"x82" or 60”x123”) of AR during Sac Peak observing time; for large AR, run more large fast maps (160"x164") of AR during Sac Peak observing time.

 request to XRT
Run a flare program, to be chosen by planner.

 request to EIS
For this flare HOP, the EIS CO should choose an appropriate flare study from the list at:

http://www.mssl.ucl.ac.uk/www_solar/eisflarestudy.html

Please ensure that a context study such as PRY_slot_context_v3 is run at the beginning and end of the sequence. Do not interrupt the sequence for SAA periods. The pointing position should overlap with the IRIS study.

 other participating instruments
REQUEST to IRIS: IRIS will allow us to get information of the dynamics in the transition region and corona of the AR.  

- Run a context raster (very large coarse 64-step, OBSID 3800256145) of the region of interest with all the spectral channels of the SJI before and after Sac Peak observing time. AEC on.

- Very large sit-and-stare (OBSID 3860258404 in case of 8s exposures, run faster if telemetry allows), sparse 2-step (OBSID 3860258410), or dense 4-step raster (OBSID 3860258416), with exposure times of less than 8 s, AEC on, rotation tracking on, flare line list, SJI  at 1400 Å and 2796 Å, and possibly 2832 Å slow  (for alignment purposes).

If possible, roll to have slit across neutral line, ideally the flare footpoints will be along the slit.

 remarks
TARGET for HINODE and IRIS:
Our target will be the active region most likely to produce a flare. The rasters should be done across the neutral line, possibly requiring IRIS to roll.

Note that the SOT FOV is internally shifted to the South by 25 arcsec, independent of the usual SOT offset that is well-known to CPs and COs.  THEREFORE, HINODE POINTING (corrected for the usual SOT offset) SHOULD AIM 25 ARCSEC NORTH OF THE ACTUAL TARGET COORDINATES USED BY IRIS.

The observing time window to match Sac Peak observations will be between 14-18 UT. In addition, any context observations during other timeframes are welcome.

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