JOP178 Filament and its environment (footpoints and filament channel) ===================================================================== Short title: JOP178 Filament and its environment PI: Thierry Roudier Observatoire Midi-Pyrenees, France Current version: 2 september 2005 Revision history: Draft June 2004 2 July 2004 (TRACE program fixed) 9 September 2004 (added more scientists) 30 July 2004 (S. Keil added) 20 January 2005 (ground based details added ++) 28 January 2005 ( M. Svanda ,J Staiger added) 2 september 2005( D. Pallamraju ,K.S.Balasubramaiam added) Coordinated observing campaign with SOHO, TRACE, and GBOs Scientists and institutes: G. Aulanier Observatoire de Paris, Meudon, France A. Berlicki Observatoire de Paris, Meudon, France J.M. Malherbe Observatoire de Paris, Meudon, France P. Mein Observatoire de Paris, Meudon, France E. Pariat Observatoire de Paris, Meudon, France B. Schmieder Observatoire de Paris, Meudon, France N.Mein Observatoire de Paris, Meudon, France J. Moity Observatoire de Paris, Meudon, France V.Bommier Observatoire de Paris, Meudon, France G. Molodij Observatoire de Paris, Meudon, France Ch. Coutard Observatoire de Paris, Meudon, France K. Bocchialini Institut d'Astrophysique Spatiale France G. Pouget Institut d'Astrophysique Spatiale France J. Solomon Institut d'Astrophysique Spatiale France T. Roudier PI Observatoire Midi-Pyrenees, France S. Rondi Observatoire Midi-Pyrenees, France N. Meunier Observatoire Midi-Pyrenees, France M. Rieutord Observatoire Midi-Pyrenees, France P. Suetterlin Universiteit Utrecht, Utrecht, Netherlands M. Svanda Astronomical Institute Ondrejov Czech Republic K. Tziotziou Universiteit Utrecht, Utrecht, Netherlands Steve Keil Sacramento Peak Observatory (USA) K.S.Balasubramaiam Sacramento Peak Observatory (USA) DENG Yuanyong Huairou Solar Observing Station (China) J Staiger KIS-Freiburg- VTT (Germany) D. Pallamraju Hida and kwasan observatories (Japan) (http://www.kwasan.kyoto-u.ac.jp/index_en.html) Participating instruments: TRACE (EOF GSFC) SOHO MDI CDS EIT (EOF GSFC) VTT (Vacuum Tower Telescope, Tenerife) ** THEMIS (Tenerife) NST (Swedish Solar Telescope, La Palma) ** DOT (Dutch Open Telescope, La Palma) DST (Dunn Solar Telescope, Sac Peak) * MST (Meudon Solar Tower, Meudon) Spectro Lunette Jean Rosch (Pic du Midi) * SOLIS * ISOON * Coronograph Bialkov Spectrograph Ondrejov Huairou Solar Observing Station (China) ** instruments not available for campaign in 2004 * instrument partially available for 2004 Number of days: 15 days required (at all the observatories) Scientific Objective and justification: Four goals should be achieved with this program. 1. The first objective is to study at the same time the photospheric and chromospheric motions around filaments. Filaments are one of the most observed features on the Sun. They are located in the upper solar atmosphere and are submitted to the effects of the lower layer, the photosphere. On basis of detailed observations, it is widely believed that the medium which transfers perturbations into the corona through the filament is a magnetic field. Since the interaction between photospheric motions and magnetic fields extending into the corona plays an important role in the dynamics of filaments, it is natural to investigate how material moves under the filament and how coronal magnetic fields evolve when a particular kind of photospheric motion is imposed at their footpoints. The aim of the program is to detect the torsion and shearing motions around the footpoints of the filaments. Such measurements are possible (Roudier et al 1999, Rieutord et al. 2001) and will be done in the areas corresponding to the footpoints where magnetic parasitic polaritic are frequently observed (Aulanier et al 1998, Martin etal 1996) 2. The second objective is to understand the environment of the filament inside the corona. Recent observations (Heinzel et al 2001, Schmieder et al 2002, 2004) show that cool material could exist below or around filaments and be not visible in Halpha because of low optical thickness but be visible as dark absorbing features in the transition region and coronal lines. The mass of filament could be twice as much as what is commonly believed. Filament eruptions are associated with some Coronal mass ejections (CMEs). Therefore the mass loading of a filament should be estimated with some accuracy. Target a filament , not too far from the equator, on the East side of the Sun at the beginning of the campaign. A filament in a region of low-medium magnetic field (100 to 400 G) 3. The third objective is to follow the passage of a filament from the disk to the limb where it becomes a prominence. On the disk, the photospheric underlying magnetic field would be obtained as usual by interpretation of the Zeeman effect, and on the limb the prominence field would be obtained by interpretation of the Ha Aulanier G., and Demoulin P., "3D magnetic configurations supporting prominences Aulanier G. and Schmieder B., "The magnetic nature of wide EUV filament channels Bommier, V., Rayrole J., and Eff-Darwich, A., "Vector magnetic field map at the photospheric level below and around a solar filament (neutral line)", 2005, A&A (Heinzel P., Schmieder B. and Tziotziou K, "Why are solar EUV filaments more extended ?Heinzel P., Anzer U. and Schmieder B., "A spectroscopic model of EUV filaments", Schmieder B., Tziotziou K., Heinzel P., "Spectroscopic diagnostics of an H_alpha Schwartz P., Heinzel P., Anzer U., and Schmieder B., "Determination of the 3D top Target:d by SOHO and VTT/MSDP", 2004, A&A 421, 323 A filament located near the central meridian at the beginning of the campaign, in a region of low-medium magnetic field (100 to 400 G). A vector magnetic field filters images interleaved about 30 s cadence, strictly regular cadence, Dopplergrams, magnetograms and Igrams in 1me filament channel. 4) Fourth objective : oscillations in Filaments and Prominences Purpose: To find long period oscillations in filaments and prominences, and to derive a diagnostic of these structures. Method: From the identification of the MHD modes derived from the observations, Joarder and Roberts (1993) model leads to 3 equations linking these modes with the alfven velocity, the temperature and the angle (between the filament and the magnetic field lines supporting the filament). Long time observations (>15h) with a high temporal resolution (less than 30s) are needed to detect -if they exist- all the periods (up to 5 or 6 hours) useful to derive these 3 parameters. We plan to observe filaments near the central meridian with CDS in He I (584 angstrom), Mg X (625 angstrom) and O V (629 angstrom), in a "sit and stare" slit configuration ; the solar rotation will be compensated (see the CDS study POUGET_3). When those filaments reach the limb, we plan to observe them as prominences with CDS and SUMER. EIT (He II at 304 A, in CME watch mode) will give the context of the observed region. THEMIS observations of the magnetic field around the filament will help in the determination of the angle mentioned above and in the determination of the distance between the opposite polarities which is also an important parameter of the model. nota: special observations required : SUMER : HeI at 584.33 A temporal resolution : ~30s slit : 0.3"x120" no rotation compensation CDS : He I 584.33A, Mg X 624.94 A, OV 629.73 A slit : 2"x240" without raster temporal resolution : ~20s study POUGET_3 EIT : 304 Å CME Watch (half res) preferable THEMIS : Magnetic field map near the filament. References: Joarder, P.S., Roberts, B., 1992, A&A, 277, 225 Regnier, S., Solomon, J, Vial, J.C., 2001, A&A, 376, 292 Pouget, G., Bocchialini, K., Solomon, J., 2005, in preparatio OBSERVATIONS 1) SST observations: observations cadence 20-30~second with Adaptative Optic. 1)H~alpha 2)the G band 3)Magnetic Field FeI (630.25) 4)V_Doppler Ni (676.8) 2)Standard DOT observations: 1)co-spatial synchronous image sequences taken in blue and red continua, 2)the G band 3)tunable wideband Ca~II~H 4)tunable narrowband H~alpha, 5) with six identical speckle cameras taking consecutive speckle bursts during as long as eight hours at 20-30~second speckle burst sampling cadence. The field of view covers up to 90~x~70~arcsec at 0.071~arcsec pixel resolution 3) The MSDP spectrograph (in H-alpha) of Meudon Solar Tower. The pixel size will be 0.5 arcsec, the field of view 72 arcsec * 462 arcsec * 5 fields (4'x7') and the cadence of the frames 2/min. 4) THEMIS magnetic field( 6301-6302 Angs., 5250 Angs), Halpha 5) White Light observation at the Pic du Midi Observatory (Turret Dome 50 cm) Pixel size=0.1, field of view 2'*2', cadence=10 frames each 15sec. 6) Sacramento Peak (USA), WL and H-alpha images 7) Huairou Solar Observing Station (China) Observation of the magnetic field and dopplergram with FeI 5324 and H_beta. We can have full-disc H_alpha filtergram with very high cadence (< 10s) too. 8) VVT (Tenerife) MSDP used for high spatial and temporal resolution imaging spectroscopy of Halpha and 8542 CaII. 9) SOLIS magnetic field Full Sun 10) ISOON Halpha Full Sun 11) Observing Sequences for SOHO and TRACE: TRACE_a : WL,1600,1700 in about 30 s cadence, strictly regular cadence No other images interleaved! 2 hours TRACE_b: filters: WL, 171, 1600 171: 768 x 768 FOV (if possible) to get the filament channel. cadence should be around 60 sec during 2 hours trace_a alternated with trace_b 08:00 UT - 10 UT TRACE_a 10:00 UT - 12 UT TRACE_b 12:00 UT - 14 UT TRACE_a 14:00 UT - 16 UT TRACE_b 16:00 UT - 18 UT TRACE_a ........... and so on 12)MDI: For a target inside the HR FOV: hr_t2_ve_fe_me (Doppler grams, magnetograms and Igrams in 1 min cadence) Otherwise a full disk 3 variable program in 1 min cadence 13)CDS -ARCONT_1 4x4' raster (has Si XII, He I, OIV, Ca X , Si IX, Mg X, Ov and Ne VI ) 14)EIT 195 CME watch with 304 during some time period will be useful. BACKGROUND OBSERVATIONS Background observations if no filament are visible on the Sun: - we observe a sunspot region - if there is no filament, no sunspot, we observe facules close to the disk centre of the Sun - if there is no filament, no sunspot, no facule, we observe the disk centre of the sun.