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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0073

CORE Too: Quiescent Prominence Structure and Dynamics

plan term


@ @


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

contact person in HINODE team

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

 abstract of observational proposal
Prominences consist of partially ionized gas at chromospheric temperatures of ~10,000 K at heights of 10--30 Mm above the photosphere - heights normally associated with fully-ionized 1,000,000 K coronal plasma. Quiescent prominences (QPs) occur primarily at high latitudes over the polarity inversion line (PIL) between network patches of opposite polarity. Hinode/SOT observations to date show that QPs are highly dynamic with vertical downflows confined in narrow "streams", intermittent turbulent upflows seen in the form of dark plumes rising through the bright prominence emission (Berger et al., 2008), vortex flows that can span several Mm in diameter, and occasional large "bubble" instabilities that can temporarily disrupt the large-scale structure of the prominence (deToma et al. 2008). Understanding prominence dynamics, and in particular instability modes, is crucial to further study of Coronal Mass Ejections, the cores of which often contain prominence mass launched within the CME.

This HOP seeks to understand further the structure and dynamics of QPs, and in particular the origin of the dark turbulent upflows and large bubble instabilities. Berger et al. (2009) have established that a magnetic Rayleigh-Taylor instability is the mechanism responsible for plume formation. In this finding, the plumes are generated from cavities that emerge from below the prominence and then undergo RT instability on the cavity/prominence interface. The larger bubbles are cavities that do not undergo RT instability for some as-yet-unknown reason. The cavities/bubbles are currently thought to be emerging twisted flux ropes but this remains to be observationally verified. We also speculate that the cavities/bubbles are thermally enhanced regions such that the buoyancy driving the RT instability is both magnetic and thermal in origin.

Due to the limited wavelength choices in the Hinode/SOT instrument, we seek coordinated observations with the TRACE, SOHO/SUMER and STEREO/SECCHI instruments in order to achieve an expanded spectral range and thus measure the temperature and density in the cavities/bubbles. TRACE will provide 171A and/or 195A absorption images, SUMER will provide high spectral resolution scans in transition region lines such as C III 1175A, and SECCHI will provide high cadence He II 304A movies.The use of ground-based telescopes such as the Swedish Solar Telescope (SST) and Dutch Open Telescope (DOT) on La Palma allow the possibility of higher spatial resolution (SST) and cadence observations than can be achieved with SOT.

This HOP should be used for prominences on the limb. It should be coordinated with HOP 139 which observes filaments on the disk. The ideal sequence would thus be to track a filament from disk center using HOP 139 and then switch to HOP 73 when the filament becomes a prominence above the limb.

Note that as of December 2009 we have removed the on-disk component of this HOP in favor of HOP 139.

Berger, T. E. et al., ApJ, 676, L89, 2008.
Berger, T. E. et al., ApJ, submitted 2009.
Bommier, V. et al., SolPhys, 154, 231, 1994.
De Toma, G. et al., ApJ Letters, submitted, 2008.
Merenda, L. et al., ApJ, 642, 554, 2006.

 request to SOT
Very high cadence filtergrams and dopplergrams.

FG: Prog. 0x0387
NFI: Halpha }208mA DG, 1408x1408, 2x2 sum, 500 msec exposure.
BFI: Ca II H-line, 2K x 2K, 2x2 sum, 500 msec exposure.
ROI shift for off-limb.
Cadence = 10\20 seconds.

See also Prog. 0x038d for very fast (5 sec cadence) Ca H 1x1 images. Use this program after a successful period of Prog. 0x0387 to try and get maximum temporal resolution of the prominence dynamics at the limb.

 request to XRT
Optimized for cavity observations
XOB#: 1371 (Lin)
Filter : Al/Poly
FOV : 512x512" with 1x1"-res and 2048x2048" with 2x2"-res
Exposure : non-saturated AEC and 4096 msec (fixed) cadence : 30 s and 1 min

Filters and exposure times:
Al-mesh (8 sec)
Al-poly (12 sec)
C-poly (16 sec)
Ti-poly (16 sec)
Al-poly + Ti/poly (23 sec)
thin Be (65 sec)
Cadence: 5 min
Compression: DCPM (lossless)
FOV: 768x768
Binning: 2x2

Note: Long exposure times are requested, but they can be shortened if
bright features exist on the disk and safety of the instrument is an issue.
Cadence can be lengthened to ~10 minutes if necessary for telemetry.

 request to EIS
Three EIS studies are requested on each target. The total run time is approximately 3.5 hours. If the total target duration is less than 3 hours, run the studies in priority order according to the list below.

1. Study 000310: ACRONYM: prom_rast_v1

prom_rast_v1 consists in one raster taking spectra at 80 positions with 1"" steps, using the 1"" slit, with 50s exposures at each position. It runs in 1h14min, therefore it can be easily inserted in the EIS observing plans. The window height in the Y direction is taken to be 128 pixels, which is sufficient to cover the area occupied by our type of target. JPEG98 compression is used to lower the telemetry requirements. The choice of the 1"" slit allows us to aim for maximal spatial and spectral resolution. We observe in 25 spectral windows to have a wide range of lines formed at different temperatures, and allowing several density-sensitive line ratios to be used for plasma diagnostics.

Number of runs: 1
TARGET: Quiescent prominence
RASTER: scanning
SLIT: 1""
FOV: 81""x128""

The line list is the following:
ID        : 149
Acronym   : prominence_lines
Author    : Nicolas Labrosse
Date      : 18-Sep-2008
num Lines : 25

0  180.40 p Fe XI
1  184.24 p Fe X
2  185.21 p Fe VIII
3  186.74 p Fe XII
4  188.23 p Fe XI
5  191.27 p S XI
6  192.82 c Ca XVII
7  193.52 p Fe XII
8  194.94 p Fe VIII
9  196.65 p Fe XII
10 202.04 p Fe XIII
11 203.83 p Fe XIII
12 256.32 c He II
13 257.26 p Fe X
14 258.37 p Si X
15 261.04 p Si X
16 262.98 p Fe XVI
17 264.23 p S X
18 270.40 p Mg VI
19 272.01 p Si X
20 274.20 p Fe XIV
21 275.35 p Si VII
22 277.13 p Si X
23 278.39 p Mg VII
24 280.75 p Mg VII

Number of runs: 1
EIS Window placement: Center just above the prominence. If no prominence is visible center above where prominence would be.
FOV: 2hx400h (100 exp sit-and-stare)
Run time: 1h14m
Objective:  characterize the dynamics of the PCTR and cavity with sit and stare.
Data Size: 180 Mb

3. GDZ_PLUME1_2_300_50s
Number of runs: 1
EIS Window placement: Center just above the prominence. If no prominence is visible center above where prominence would be.
FOV: 300hx512h
Run time: 1h05m per study
Objective: DEM analysis of cavity and PCTR
Data Size: 245 Mb per study

 other participating instruments

Request to STEREO: high cadence He II imaging.
High-cadence quadrant readout. Synoptic interruptions ok. He II 304A.

Request to TRACE: 195A EUV filtergrams.
195A; 768 x 768, 60 sec cadence, or as close to 60 sec as possible.

Legacy material:
Request to SOHO/SUMER:
1. LYA_B_RASTER study: 60" raster.  Ly-alpha/Si III 1206 + Ly-beta/OVI 1032.
2. C III 1175 + He I 584 study, 60" raster.
1" slit or 0.3" slit if count rates allow.

Request to SOHO/UVCS: coronal density diagnostics and CME watch.
When the target filament is close to the limb, UVCS will perform a CME watch
sequence above the filament at a height between 1.7 and 2 solar radii.  The
sequence will be a series of 2 minute exposures covering the O VI doublet, Lyman  beta and Si XII.

Targets: Coordinating with HOP 139, the main targets will be the largest filaments on the disk at the time of the observing program. We will observe the filaments from near central@meridian to the West limb on sequential observing days. I.e., a single filament will be chosen at the beginning of the period and this filament will be tracked across the disk until it disappears behind the limb. Ideally, there are two targets as follows:

1. Large polar crown filament near central meridian.
Track the filament to the West limb using HOP 139 and observe as a prominence for at least one day using HOP 73.

2. Active region filament.
Similar to above: track the filament to the West limb and observe as prominence.  The purpose of the AR filament observations is to contrast AR prominence and QP structure.

If there are no polar crown filaments on the disk at the time of the program, we will observe any QPs visible on either limb using HOP 73.

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