*Title: Quiescent prominence structure and dynamics with Hinode/SOT *Short title : Quiescent prominences *Authors: T. Berger (1), S. Martin (2), O. Engvold (3), S. Parenti (4) (1). Lockheed Martin Solar and Astrophysics Laboratory (2). Helio Research (3). Institute for Theoretical Astrophysics, University of Oslo (4). Royal Observatory of Belgium *Contact: berger (at) lmsal.com *Update History: First Draft (July 17, 2008) Second Draft (August 29, 2008) Third Draft (January 9, 2009) Fourth Draft (March 6, 2009) *Participating instruments and observatories SOHO/SUMER SOHO/UVCS Hinode/SOT Hinode/XRT Hinode/EIS STEREO/SECCHI TRACE *Scientific Justification Recent SOT observations have discovered highly dynamic features in quiescent prominences (Berger et al. 2008). Some of the features such as filamentary down-flow streams, large scale vortex flows, and oscillations have been seen occasionally in previous ground-based observations. However the Hinode/SOT movies also show the existence of dark turbulent up-flow plumes that rise with nearly constant velocities around 20 km/sec. In addition, large "bubbles", sometimes spanning 50 Mm or more in diameter, are seen to occasionally "inflate" beneath QPs. Similar bubbles have recently been noticed in Mauna Loa H-alpha movies as well (DeToma et al. 2008). These highly dynamic vertically propagating features are hard to reconcile with the classic theories of prominences in which the gas is quasi-statically suspended against gravity by horizontal magnetic fields. Complicating matters, most measurements to date find horizontal magnetic fields in prominences (Bommier et al., 1994, Casini et al. ; however see Merenda et al. 2006 for a dissenting observation), in support of the horizontal suspension models. The ubiquitous filamentary down-flows are particularly difficult to incorporate into these classical prominence findings. E.g., how can vertical down-flow streams with speeds on the order of 10 km/sec be compatible with relatively low-beta concepts of prominence suspension in horizontal magnetic fields? This JOP seeks to further understand the structure and dynamics of QPs, and in particular the origin of the mysterious dark turbulent up-flows and large bubble instabilities. Can we discern a thermal mechanism at work in these dynamics? Or are they caused, as the more classical explanation would have it, by magnetic field dynamics entraining the plasma in a low-beta mode? Due to the limited wavelength choices in the Hinode/SOT instrument, we seek coordinated observations with SOHO/SUMER, STEREO/SECCHI, and TRACE instruments in order to achieve an expanded spectral range. TRACE will provide 195A absorption images, SUMER will provide high spectral resolution scans in cool transition region lines such as Si III 1206, Si IV 1408, and Lyman-alpha and beta, and SECCHI will provide high cadence He II 304A. These combinations will allow us to more successfully study QPs in both their on-disk appearance as filaments as well as their off-limb appearance as prominences. While most QPs in the SOT database appear to be composed of vertical threads, others can appear primarily horizontal or as a mix of horizontal and vertical structure. In this JOP we will emphasize observations of on-disk filaments that can be tracked to the West limb and subsequently observed as prominences in order to discern the role that line-of-sight angle plays in prominence appearance at the limb. Berger, T. E. et al., ApJ, 676, L89, 2008. Bommier, V. et al., SolPhys, 154, 231, 1994. De Toma, G. et al., ApJ 687, L123, 2008. Merenda, L. et al., ApJ, 642, 554, 2006. *Date and Time Information The JOP is requested to be run during the April 2009 SUMER/Hinode campaign. For this run, there are no ground-based observing constraints and the program can be run at any hour. *Targeting Requirements The main target will be the largest filament on the disk at the time of the observing program. We will observe the filament 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. The primary and alternate plans are as follows: 1. Large polar crown filament at about 20 degrees West heliographic longitude. Track the filament to the West limb and observe as a prominence for at least one day. 2. Alternate plans in case of no filaments on the disk. (a) Large polar crown prominence on the East limb, tracked over several days onto the disk. (b) Any prominence on the West limb. *Detailed Observing Sequences per Instrument 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. UVCS: 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. Hinode/SOT: The SOT observing requirements are different for on-disk filament or off-limb prominence observations. A. On-disk Filament Observations NFI: H-alpha line-center & Na I 589.6 nm shuttered IVDG, 1408 x 1408, 2x2 sum. BFI: G-band 403.5 nm, 2K x 2K, 2x2 sum. Ca II 396.8 nm H-line, 2k x2k, 2x2 sum. Cadence = 40-60 seconds, depending on telemetry allowance. SP: Fast Map 100" x 80" (sub-slit readout) scan. Cadence: repeat once per hour. Note: SP scans are not practical within about 20 deg heliographic latitude from limb. B. Off-limb Prominence Observations 1. Prog. 0x01bf NFI: H-alpha +/- 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 = 20-30 seconds. 2. Prog. 0x02b7 Ca II H-line 1.6 sec cadence ROI shift for off-limb. Program 1 run for 3 hours, Program 2 run for 0.5 hour (telemetry allowing). Hinode/XRT: only required for off-limb prominence observations. Goal is to see the coronal cavity in highest contrast. XOB#: 1371 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 Occasionally the Gband Hinode/EIS: 136x400 slot movies He II, Mg VI, and Si VII Q75 compression or higher Cadence: 70 seconds, higher if possible. STEREO/SECCHI High cadence He II 304A images are requested during the SUMER observing times. TRACE: Fe XII 195A 768x768 100 cadence, Q0 compression during radiation free times. Remnant programs from the 2008 ground-based campaign: SST/La Palma: On disk: CRISP H-alpha 656.3 nm dopplergrams (min. 4 point line sample) Fe I 557.6 nm dopplergrams Fe I 630.2 nm magnetograms G-band 430.5 nm filtergrams Off disk: CRISP H-alpha 656.3 nm and Ca II 854.2 nm dopplergrams Ca II H- or K-line filtergram Cadence: 20 seconds maximum Note: the SST may not be capable of off-disk imaging due to AO locking requirements. DOT/La Palma: H-alpha dopplergram (+/- 200 mA+ LC) On disk: G-band 430.5 nm filtergrams Off disk: Ca II H- or K-line filtergrams or 8542A filtergrams if available. Cadence: 10 seconds