Solar-B JOPs M. Weber, B. De Pontieu, & E. Landi Solar-B MO/DA, NRL, Oct-2005 This text file concatenates two JOP descriptions. These JOPs were designed jointly among the three Solar-B instrument teams, and they serve several purposes: (a) To demonstrate coordinated observing programs among all three instruments, with varying emphasis on the amounts of support; (b) To demonstrate some of the capabilities, strengths, and flexibilities the different instruments bring to bear on mutual scientific investigations; (c) To provide two examples of template/format upon which to build future JOPs; and (d) To get at least two Solar-B JOPs actually written! JOP 001: Active Region Loops JOP 002: Spicules ============================================================================== JOP 001: ACTIVE REGION LOOPS ------------------- E. Landi (EIS), B. De Pontieu (FPP/SOT), M. Weber (XRT) SCIENTIFIC JUSTIFICATION Plasma loops are the building blocks of the inner solar atmosphere, and they dominate the structure and the evolution of the quiet and active Sun. In active regions, plasma loops are involved in all aspects of plasma dynamics, energetics, and activity. Understanding the physics and the evolution of active regions in order to predict its flare and CME activities requires a precise knowledge of the mechanisms that create, heat, evolve and dissolve active region loops as a preliminary step. The importance of loops in active region has triggered a multi-decade effort to model their structure and behavior, but all attempts have been so far demonstrated to be insufficient by observations. The SOHO, TRACE and Yohkoh satellites have been widely used to observe active region loops, and their observations have shown that 1) predicted temperature and density profiles disagree with observations; 2) predicted temperatures are usually too high; 3) predicted footpoint emission is far too high than observed. Crucial, basic questions about the physics of solar loops still remain open: how is loop plasma heated? Is loop plasma composition constant or does it change with time? Why is loop plasma composition different from the photosphere, from where loops emerge? Are loops monolithic isothermal structures, or are they composed of many subresolution strands at different temperatures? Is loop cross-section constant or does it vary along the loop? Only by answering such questions can we hope to gain a clear picture of the physics of loops and of active region and to develop tools that can allow us to forecast the occurrence and the strength of the largest activity events in active regions, such as flares and CMEs, that have so large an impact on space weather and are so full of consequences for human exploration of space. Plasma diagnostics and dynamics studies can be best carried out by spectrometers, while high cadence can be mostly achieved by narrow-band imagers. However, current instrumentation has failed to provide us with observations of high enough quality to allow us to address the above open problems. Current spectrometers' lack of sufficient spatial or spectral resolution, low cadence, limited simultaneous multitemperature coverage and lack of suitable diagnostic line pairs have hindered efforts to gain a quantitative picture of active region loop physics; in turn, these limitations have prevented an effective coordination with the available narrow-band imagers. Solar-B will revolutionize our studies in loop physics: for the first time, the EIS spectrometer will allow us to observe solar active region loops with the necessary high spatial and spectral resolution and high cadence observations of diagnostic line pairs to measure the physical properties of active region loops; EIS design and expected performance will allow us to exploit at an unprecedented level the potential of the coordinated observations with the other two Solar-B instruments, FPP and XRT. SCIENTIFIC OBJECTIVES AND REQUIREMENTS There are several areas of investigation that need to be pursued in order to understand active region loops. Different sets of physical properties can be observed and compared to theoretical model, in order to unambiguously validate of confute them: 1 - Measure the temperature and density profile of loops along the loop length; 2 - Determine plasma flows in active region loops; 3 - Investigate loop shapes at different temperatures, and compare them with XRT images, to determine cospatiality of emission generated by plasma at different temperatures; 4 - Determine loop shapes in the entire active region, and compare them to the extrapolations of photospheric magnetic field measurements from FPP; 5 - Study the intensity of emission of lines formed in a wide range of temperature to determine the shape of the loop cross-section; 6 - Measure the thermal structure of the loop {\em across} the loop cross-section, to investigate the presence of multi-thermal, subresolution strands; 7 - Study the temporal evolution of element abundances in individual loops structures, by using Fe and S lines, in order to study the FIP effect. OBSERVING PROGRAMS TARGET SELECTION: Successful observations of active region loop physical properties requires several different modes of observation. The most important data set will consist of continuous observations of a wide field of view centered on an active region. To monitor the evolution of individual loops in time, it is necessary to observe the active region from close to the east limb to the disappearance at the west limb. Individual loops can be studied in more detail and faster cadence by adopting smaller fields of view. EIS ----- FIELD OF VIEW: 256"x256", to include the entire active region, for the continuous observations of the active region across the solar disk (main raster). Loop footpoints and targeted loop studies require a 64"x64" field of view (small raster). Fast monochromatic imaging (slot raster) needs to cover the same field of view of the main raster. RESOLUTION: 1" for the continuous observations of the active region and the small raster, in order to maximize the spatial resolution of fine-structure details of the selected target. The 40"-wide slot will be used to build fast sequences of monochromatic images in four selected lines to complement narrow-band observations from XRT. CADENCE: 20 minutes for the main raster of the main sequence. One minute or less for fast monochromatic imaging using the 40"-wide slot. Individual loops or smaller fields of view should be studied with higher cadence (10 minutes or less). LINE SELECTION: The main and small raster sequences need to include the following lines: Line log(T_max) Large Slot Small ----------------------------------------------------- He II 256 4.3 x x x Si VII 275 5.8 x x Fe XI 188 6.1 x x Fe XII 186 6.2 x x 193 6.2 x 195 6.2 x x Fe XIII 202 6.3 x x x 203 6.3 x x S XI 285 6.3 x x Fe XIV 274 6.4 x x Fe XV 284 6.5 x x x Fe XVI 263 6.6 x x Raster Slit N_steps FOV t_exp Cadence Telemetry N_lines N_pixel Size (s) (min) (kbit/s) (A) ------------------------------------------------------------------------------------ Large 1" 256 256"x256" 5 21.3 54.1 11 16 0.357 Small 1" 64 64"x 64" 5 5.3 13.5 11 16 0.357 Slot 40" 6 240"x256" 5 0.5 49.2 4 40 0.892 Table 1. Summary of EIS raster requirements. XRT ----- FIELD OF VIEW: The PFI pointing will be centered on FPP and EIS field of view. (PFI = Partial Frame Image. FFI = Full Frame Image.) Two modes of observations: Study A: Fast loop motions; bursty data rate over 3 hours. This observing program emphasizes speed with a 10-sec cadence. The use of two filters allows some discrimination of loop plasma temperatures. Observations can be continued for up to 3 hours. Study B: Loop temperatures and dynamics; sustainable data rate. This observing program balances excellent temperature coverage with a cadence fast enough to observe loop evolution and plasma motions. Observations are at the limit of a sustainable rate. RESOLUTION: both observing modes will have 1"/pixel, with no rebinning. CADENCE: Study A: PFIs: 2 channels every 10s, interrupted every 15 minutes by the FFIs. FFIs: 3 channels in 30s, every 15 minutes. G-band: 1 channel, every 15 minutes. Study B: PFIs: 4 channels every 35s, interrupted every 15 minutes by the FFIs. FFIs: 3 channels in 30s, every 15 minutes. G-band: 1 channel, every 15 minutes. Image Channels FOV Pixel Cadence Compression type size (s) mode ---------------------------------------------------------------------------------------------------------- Study A: FFI {Al/poly, C/poly, Be/thin} 2048"x2048" 1" 900 JPEG lossy FFI {G-band} 512"x512" 1" 900 JPEG lossy PFI {Al/poly, C/poly} 256"x256" 1" 10 lossless Data rate (kbit/s) = 107 Telemetry (kbit/s) = 69 ==> On-board storage rate (kbit/s) = 38 1/6 DR (Mbit) = 450 ==> Fill time = 3.3 hrs Study B: FFI {Al/poly, C/poly, Be/thin} 2048"x2048" 1" 900 JPEG lossy FFI {G-band} 512"x512" 1" 900 JPEG lossy PFI {Al/poly, C/poly, Be/thin, Be/med} 256"x256" 1" 35 lossless Data rate (kbit/s) = 72 Telemetry (kbit/s) = 69 ==> On-board storage rate (kbit/s) = 3 1/6 DR (Mbit) = 450 ==> ~ indefinitely sustainable data rate SOT/FPP ------- FIELD OF VIEW: In order to have suitable cadence, the field of view will be restricted to 160"x160", sufficient to observe both footpoints of most active region loops (shorter than 110,000 km) and the wide areas surrounding them. RESOLUTION: 0.16" pixels will be used, obtained through 2x2 rebinning, in order to 1) precisely determine the location of the loop footpoints in the field of view, and 2) to study the small-scale activity around the loop footpoints, and its relationship with larger scale phenomena involving one or more loops. CADENCE: 60~s cadence can be obtained for observations of H-alpha filtergrams and of photospheric vector magnetograms; 120s cadence can be obtained for observations of H-alpha filtergrams and photospheric and chromospheric vector magnetograms. To achieve the 60s cadence, only one vector magnetogram can be transmitted (fast sequence), both magnetograms can be transmitted only with a 120s cadence (slow sequence). LINE SELECTION: Filtergrams: H-alpha 6563 A photospheric vector magnetograms: Fe I 6302 A chromospheric vector magnetograms: Mg Ib 5172 A Fast sequence Slow sequence Option A Option B -------------------------------------------------------------------------------- NFI images 17 17 33 N.pixels 1000x1000 1000x1000 1000x1000 Rebinning 2x2 2x2 2x2 Filtergram H-alpha 6563 A H-alpha 6563 A H-alpha 6563 A Vector magn. Fe I 6302 A (phot) Fe I 6302 A (phot) Mg Ib 5172 A (chrom.) Mg Ib 5172 A (chrom.) t_exp (s/image) 0.5 0.5 0.5 Cadence (s) 60 60 120 Table 2. Summary of FPP data requirements DATA REQUIREMENTS The dataset will consist of a set of calibrated, co-aligned, cleaned spectra, monochromatic and narrow-band images and vector magnetic maps for active regions and individual loops, observed over time while they cross the solar disk. SUPPORTING REQUIREMENTS Required: 1 - PLASMA DIAGNOSTIC TOOLS: necessary to measure physical parameters from observed line intensities, widths and shifts, line ratios, filter count rates and filter ratios. These tools are already available through the CHIANTI database and software. 2 - THEORETICAL LOOP MODELS: necessary to compare with observations to discriminate between different heating mechanisms, multi-thermal strands or monolithic models, FIP effect models. Many models are already available, but will need to be modified/improved during the mission in response to observations (and will be used to build new observing sequences to address new theoretical models). 3 - MAGNETIC FIELD EXTRAPOLATION TOOLS: necessary to extrapolate field lines in the corona for comparison with monochromatic and narrow-band images. Some are already available, but they will need to be improved/modified during the mission in response to observations. Optional: 1 - SOHO/SUMER COORDINATED OBSERVATIONS: SOHO/SUMER can observe at 1" spatial resolution a large number of chromospheric and transition region lines, complementing the Solar-B instruments. These data can be used to study loop footpoints, loop abundances, and measure the physical properties of the coldest portions of the loop plasma. These observations can be very useful to characterize the loops footpoints, and study the shape of the loop cross-section and of the loop heating. ============================================================================== ============================================================================== JOP 002: Spicules: formation and impact on TR and corona Authors: Bart De Pontieu (SOT/FPP), Enrico Landi (EIS), Mark Weber (XRT) Version: 1.0 (October 11, 2005) Scientific justification The dynamic interaction of photospheric magnetic elements and the convective flow field is thought to provide much of the energy for heating and flows in the outer atmosphere. The transport and deposition of magneto-convective energy causes the intermediate regions between photosphere and corona to be in a highly dynamic and inhomogeneous state, dominated by such small-scale flows as transition region (TR) explosive events and chromospheric spicules. Spicules are dynamic jets propelled upwards from the solar surface or photosphere at speeds of ~20 km/s into the magnetized low atmosphere of the Sun, which they dominate. Spicules and their disk-equivalent, mottles, remain poorly understood. We don't understand how they form and evolve, or to what temperature they get heated, i.e., their importance for the energy and mass balance of the transition region and corona is unknown. The small size (<1") and transient nature (dynamics on times of <30 s) of spicules render high-quality observations from ground-based telescopes very difficult. This lack of observational constraints has led to a multitude of theoretical models, most of which have trouble explaining one or more properties of spicules. Solar-B will revolutionize our understanding of spicules. Solar-B's SOT/FPP seeing-free imaging of the chromosphere at high spatial resolution (~0.2-0.3") and high cadence (~20 s) will for the first time resolve the detailed spatial and temporal evolution of spicules, both at the limb and on the disk. Quasi-simultaneous magnetic field measurements at both photospheric and chromospheric heights as well as horizontal flow-field and Doppler measurements in the photosphere will provide crucial testing of many of the theoretical models describing spicule formation. The impact of spicules on the transition region and corona will also be explored in much more detail than before, through simultaneous EIS and XRT observations, and will lead to an improved understanding of the role spicules play in the mass and energy balance of the corona. Scientific objectives Since so much is unknown or contested about spicules, Solar B will be able to address a whole range of scientific objectives. In this JOP, we focus on two issues, both of which lend themselves (to some extent) to a multi-instrument approach: 1. Spicule formation: How is the presence and formation of spicules related to the horizontal and vertical (convective) flows and (p-mode) oscillations in the photosphere? Can we observe the presence of (acoustic?) shocks that are supposed to drive spicules in several models? Can we trace these shocks as they propagate upwards through the photosphere, low chromosphere, and transition region? How do they relate to the shocks that are predicted by the rebound shock model, the strong pulse model, etc...? Are spicules (sometimes?) caused by reconnection of opposite polarity on very small scales, or do they occur above unipolar regions? How are H-alpha spicules related to explosive events, if at all? Do periodic spicules occur preferentially along non-vertical magnetic flux tubes (as in the p-mode driven model)? What is the exact relationship between spicules and bright points? Do they occur before or after the spicule starts to rise? 2. Impact on TR/corona: How do chromospheric spicules relate to spicules observed at higher temperatures, such as those seen in UV observations? If they are related, how much chromospheric plasma is heated to transition region temperatures? Can we constrain the heating mechanism by detailed temporal and spatial correlation studies between UV and visible light observations? Are spicules driven by the same mechanism as macrospicules? Can we use UV/EUV spectroscopy to trace the formation and propagation of shocks from low chromosphere to corona? Observing Requirements In order to address these issues, high-resolution, high-cadence, multi-wavelength, polarimetric data of both quiet sun and active regions are necessary. The high spatial resolution is necessary to resolve the spicules, which have diameters ranging from 0.3" to 2". Temporal resolution of order 20 seconds is necessary to track the changes in spicules, which are dynamic on time scales of order 30 seconds. Multiple wavelengths and polarimetry are needed for a comprehensive study of the formation and evolution of spicules from their photospheric source up to the top of the chromosphere. Dopplergrams in both photosphere and low chromosphere will elucidate the relationship with the vertical flows and oscillations. The polarimetric observations must measure down to the weakest flux observable by SOT/FPP to investigate the possible presence of opposite polarities at the footpoints of spicules. For the high-temperature physics, EIS and XRT data should be at full resolution and at the highest possible cadence. Joint Observing Programs ------------------------ JOP 2a: Relationship between photospheric flows and oscillations, and chromospheric/TR spicules Target: active region plage or quiet Sun network on disk FOV: 64" x 64" Duration: 4 hours SOT/FPP ------- SOT/FPP: 12 NFI images of 800x800 0.08" pixels at 30 s cadence 1 BFI image of 1208x1208 0.053" pixels at 30 s cadence NFI: Fe I 6302.5 nm dopplergram/longitudinal magnetogram (4 images) Mg Ib 517.2 nm dopplergram/longitudinal magnetogram (4 images) H-alpha 656.3 nm -700/-350/+350/+700 mA filtergrams (4 images) BFI: G-band 430.5 filtergram (1 image) Telemetry: 12x800x800x1 bit per pixel + 1x1208x1208 bit per pixel = 9140 kbits at 304 kbit/s: cadence about 30 s Cadence limits: readout = 10.8 s = 0.8 s (=800/4000 * 4 s) readout per image x 12 + 1.2 s (=1200/400 * 4 s) readout per image x 1 NFI tuning = 10.5 s = 3 x 3 s + 3 x 0.5 s exposure time = 13 x 0.5 s = 6.5 s switch between NFI/BFI = 2 s total = 29.8 s, fits within 30 s EIS ----- EIS: Start with one "wide slit" (40" wide) exposure in He II 256, Si VII 275, Fe XII 193, Fe XIII 202, Fe XIV 274, Fe XV 284 for co-alignment purposes (see below for details). (9 kbits/s) 13 spectral windows containing He II 256 A, Mg V 276, Mg VI/Fe XIV 270, Mg VII/Si VII 278, Si VII 275, Fe XII 186, Fe XII 195, Fe XIII 202, Fe XIII 203, Fe XIV 264, Fe XIV 274, Fe XV 284, S XI 285 at 30 s cadence (14.2 s exp. time), read out 64" along slit, co-aligned with SOT/FPP pointing, scan 2" in E-W Telemetry: 26.6 kbit/s (see table at the end for details) XRT ----- XRT: logT=6.1 images at full resolution, partial frame of 256"x256" to provide context and study EUV absorbing spicules above plage/network. Cadence 30 s. - PFI pointing centered on SOT/FPP FOV. - Full Frame Images (FFI); FOV = 2048"x2048"; plate-scale = 1"/pix: 3 channels = {Al/poly, C/poly, Be/thin}; about 30 sec for set; one set per 10 min; JPEG lossy compression; ~25 Mb/set. - G-band (white-light) image for co-alignment; FOV = 2048"x2048"; plate-scale = 1"/pix; channel = {G-band}; 1 hour cadence; 12.6 Mb/img. If target is PLAGE: - Partial Frame Images (PFI); FOV = 256"x256"; plate-scale = 1"/pix; 4 channels = {Al/poly, C/poly, Be/thin, Be/med}; 30 sec cadence; lossless compression; ~1.57 Mb/set. - Net data rate = ~343 Mb/hr (95 kbits/s) - Allowable telemetry rate for XRT = ~250 Mb/hr (or 69 kbits/s) (This is based upon the following: 2.4 Gb/pass total; 1/6 for XRT, 20 passes per day. I am happy to review these and other numbers at the meeting next week, as I would like to confirm them among the teams.) - Therefore, the data rate exceeds the allowable telemetry by 93 Mb/hr. On-board storage for XRT = ~450 Mb. Over 4 hours, this uses ~83% of the storage. If target is QUIET SUN: - Partial Frame Images (PFI); FOV = 128"x128"; plate-scale = 1"/pix; 4 channels = {Al/poly, C/poly, Be/thin, Be/med}; 30 sec cadence; lossless compression; ~0.39 Mb/set. - Then, net data rate = 208 Mb/hr (58 kbits/s), which is well within the allowable telemetry rate. ---------------------------------------------------- JOP 2b: opposite polarities and reconnection at footpoints of spicules Target: active region plage/quiet Sun network on disk FOV: 64" x 64" (1.9"x64" for SP/EIS) Duration: 4 hours SOT/FPP ------- SOT/FPP: 10 NFI images of 800x800 0.08" pixels at 30 s cadence NFI: Fe I 630.2 nm dopplergram/longitudinal magnetogram (4 images) Mg Ib 517.2 nm dopplergram/longitudinal magnetogram (4 images) H-alpha 656.3 nm -700/-350 mA filtergrams (2 images) SP: full Stokes map of 1.9"x64" FOV in normal map mode (12 steps of 0.16" and 400 0.16" pixels along slit) Telemetry: NFI: 10x800x800x1 bit per pixel = 6400 kbits at 215 kbits/s: cadence about 30 s SP: 120x2x4x400x1 bit per pixel = 384 kbits in 5 s (one step) at 80 kbits/s: cadence about 60 s for 12 steps Cadence limits: NFI readout = 8 s = 10 x 800/4000* x 4 s NFI tuning = 10.5 s = 3 x3 s + 3 x 0.5 s NFI exposure time = 5 s = 10 x 0.5 s NFI total = 23.5 s (less than 30 s) EIS ----- EIS: Start with one "wide slit" (40" wide) exposure in He II 256, Si VII 275, Fe XII 193, Fe XIII 202, Fe XIV 274, Fe XV 284 for co-alignment purposes (see below for details). (9.2 kbits/s) 13 spectral windows containing He II 256 A, Mg V 276, Mg VI/Fe XIV 270, Mg VII/Si VII 278, Si VII 275, Fe XII 186, Fe XII 195, Fe XIII 202, Fe XIII 203, Fe XIV 264, Fe XIV 274, Fe XV 284, S XI 285 at 30 s cadence (5.2 s exp. time), read out 64" along slit, co-aligned with SOT/FPP pointing, scan 5" in E-W Telemetry: 13.3 kbit/s (see table at the end for details) EIS: He II 256 A, Mg V, Si VII, Mg VII and some hotter lines (to look for explosive events) at 30 s cadence, full resolution, read out 70" along slit, co-aligned with SOT/FPP pointing scanning: scan 5"x70" region, co-pointing with SP raster Telemetry: to be worked out (Enrico?) XRT ----- XRT: logT=6.1 images at full resolution, cutout of 256"x256" (or 128"x128") to provide context and study EUV absorbing spicules and/or heating events above plage/network. Cadence 30 s. Details same as in JOP 2a. ---------------------------------------------------- JOP 2c: chromospheric/TR spicules at the limb Target: limb region above quiet Sun or active region FOV: 64" x 64" Duration: 4 hours SOT/FPP ------- SOT/FPP:7 images of 800x800 0.08" pixels at 30 s cadence NFI: H-alpha 656.3 nm -700/-350/+350/+700 mA filtergrams (4 images) Na I D 589.6 nm -200/0/+200 mA filtergrams (3 images) Telemetry: 7x800x800x1 bit per pixel = 4480 kbits at 150 kbits/s: cadence about 30 s Cadence limits: NFI readout = 5.6 s = 7 x 800/4000* x 4 s NFI tuning = 8.5 s = 2 x 3 s + 5 x 0.5 s NFI exposure time = 3.5 s = 7 x 0.5 s NFI total = 18 s (less than 30 s) EIS ----- EIS: full spectral range, full resolution at 30 s cadence raster of 3" (E-W) x 64" (S-N) region, telemetry 157 kbits/s (but SOT/FPP only uses 150 kbits/s). For quiet Sun, actual telemetry may be significantly less since the hot lines will be very weak and not carry much signal. XRT ----- XRT: Same as in JOP 2a. ---------------------------------------------------- Additional Instruments All of these JOPs could benefit from dopplergrams and context longitudinal and vector magnetograms from respectively, SOHO/MDI and SDO/HMI. In addition, for the active region plage spicule studies, TRACE (and when available SDO/AIA) 171 and 195 A images will be very useful to study the effects on the upper transition region plasma. TRACE and SDO/AIA 1600 (C IV) images can be used for studies focusing on the relationship between chromospheric spicules and UV spicules. ---------------------------------------------------- EIS Table JOP 2a JOP 2b JOP 2c JOP Jolly ------------------------------------------------------------------------- Slit (arcsec) 1 1 1 40 Exposure time (s) 14.2 5.2 9.2 9.2 Readout time (s) 0.8 0.8 0.8 0.8 Total time (s) 15.0 6.0 10.0 10.0 Cadence (s) 30 30 30 10 n. E-W raster 2 5 3 0 n. slit pixels 64 64 64 64 n. spectral windows 13 13 2 6 n. spectral pixels/window 16 16 2048 40 spectral width/window (A) 0.357 0.357 ~ 40 0.892 Req.d Telemetry (kbit/s) 5.3 13.3 157.3 9.2 Spectral lines Full det. He II 256 x x - x Mg V 276 x x - Mg VI/Fe XIV 270 x x - Mg VII/Si VII 278 x x - Si VII 275 x x - x Fe XII 186 x x - Fe XII 193 - x Fe XII 195 x x - Fe XIII 202 x x - x Fe XIII 203 x x - Fe XIV 264 x x - Fe XIV 274 x x - x Fe XV 284 x x - x S XI 285 x x - ------------------------------------------------------------------------- Possible co-alignment strategies 1. use SOT/FPP H-alpha, Ca II H or some other chromospheric images and find the offset with the EIS wide slit images in the cold lines. In more active regions, we can also use the dark, EUV absorbing features in the 193/195 A wide slit images to co-align them with SOT/FPP H-alpha images (+- 350 mA). The latter procedure has been used succesfully using ground-based and TRACE data. 2. co-align the EIS hot slot window (e.g. 193/195) and co-align with an XRT image at log T=6.1. Maybe we can use the "white light" channel images from XRT to co-align them with (much higher resolution) white light images from SOT/FPP? ----------------------------------------------------