Title ----- Multi-wavelength Observations of Oscillations in Polar Plumes Short Title ----------- Oscillations in Polar Plumes Proposers --------- James McLaughlin, University of St Andrews, james (at) mcs.st-andrews.ac.uk Ineke De Moortel, University of St Andrews, ineke (at) mcs.st-andrews.ac.uk Alan Hood, University of St Andrews, alan (at) mcs.st-andrews.ac.uk Danielle Bewsher, STFC/RAL, danielle.bewsher (at) stfc.ac.uk Craig DeForest, Southwest Research Institute, deforest (at) boulder.swri.edu Update History -------------- [1] This is version 3 (03-FEB-09) of this proposal. [2] Hinode observations (EIS, SOT, XRT) are designated HOP 98: http://www.isas.jaxa.jp/home/solar/hinode_op/hop.php?hop=0098 Participating Instruments ------------------------- Hinode/EIS (POC: Len Culhane, jlc (at) mssl.ucl.ac.uk) Hinode/SOT (POC: Tom Berger, berger (at) lmsal.com) Hinode/XRT (POC: Leon Golub, golub (at) head.cfa.harvard.edu) SOHO/CDS (POC: Andrzej Fludra, andrzej.fludra (at) stfc.ac.uk) SOHO/EIT (POC: Joe Gurman, gurman (at) gsfc.nasa.gov) STEREO/EUVI (POC: Simon Plunkett, simon.plunkett (at) nrl.navy.mil) TRACE (POC: Karel Schrijver, schrijver (at) lmsal.com) Scientific Objectives --------------------- To detect the (propagating) fast magneto-acoustic wave and Alfven wave in polar plumes, and to determine the fundamental physical parameters (morphology, density, temperature profile, composition, flows) of these plumes using multi-wavelength observations from several satellites. Science Case ------------ This Joint Observing Programme between Hinode, STEREO, TRACE and SoHO aims to investigate the nature of oscillations in solar polar plumes. Polar plumes are denser than the surrounding material and so are natural wave guides for the three MHD modes, namely Alfven, fast and slow magneto-acoustic waves. However, so far only one of the three modes has been detected (the slow mode) (DeForest & Gurman 1998). This HOP/JOP aims to detect these two 'missing' modes using high spatial and temporal resolution imaging and spectroscopy. In addition, we will obtain a significant improvement to our understanding of the morphology, density, temperature profile and composition of polar plumes. Such an investigation is of high scientific value for three reasons. Firstly, the two missing modes are theoretically predicted and so their detection would be a significant contribution to the study of MHD wave theory, and validation of its application. Secondly, this HOP/JOP will significantly improve current estimates (DeForest et al. 1997) of the properties of polar plumes (such fundamental properties are essential in order to accurately interpret and evaluate the modes). Thirdly, these wave modes feed directly into the fast solar wind. Thus, a detailed understanding of their properties is needed to accurately determine their energy flux contribution and their role in the acceleration of the fast solar wind. This aims of this HOP/JOP are: 1) To determine the fundamental properties of polar plumes. 2) To detect the fast magneto-acoustic and Alfven waves in polar plumes. 3) To investigate the underlying driving mechanism of these wave motion (are the modes coupled to oscillations in the lower atmosphere, or driven by reconnection events). 4) To uncover what governs the life-cycle of polar plumes (how and where do they form, are they created by jets, what physical processes govern when they disappear). We propose a two part campaign taking both spectroscopic and imaging data at multiple wavelengths. This will consist of a "lifetime campaign" for 6 hours (lower resolution, mostly synoptic), followed by a "high cadence campaign" for two hours followed by a second "lifetime campaign" for 24 hours. The high resolution part of this JOP gives us the best chance of observing wave motions, and the data on either side will allow us to investigate the entire life cycle (addressing how and where do plumes form, and what physical processes govern when they disappear) and overall evolution. The 2 hour, high-cadence part of the campaign aims to detect wave motions. To detect the fast waves, we shall use TRACE (30 second cadence and 1'' spatial resolution) and both STEREO/EUVI instruments (30 second cadence, 1.6''). The unique stereoscopic view points of the STEREO satellites will allow us to determine if the fast waves propagate with 3D motion, e.g. helical kink motions. We expect the fast wave to have a period of the order of several minutes, so 30 second cadence should be sufficient for a conclusive detection. To detect the Alfven wave, we will look for evidence of non-thermal line broadening using SoHO/CDS and Hinode/EIS. We shall also observe slow waves (as in DeForest & Gurman 1998) and aim to improve the statistics of their properties in plumes, and to investigate their relation to slow waves in coronal loops. In addition, data from Hinode/SOT will allow us to glimpse the chromospheric motions within plumes, shedding light on the underlying physical driving mechanism. A photospheric vector magnetogram taken with Hinode/NFI will allow realistic theoretical modelling in order to directly compare with observations. Hinode/XRT will give critical insights into the heating profile and we will look for evidence that reconnection jets are the precursors to plume formation (Raouafi et al. 2008). Finally, we shall use SoHO/EIT to give context to our whole campaign: Plumes are most easily identified using EIT (and thus its involvement is essential) and the original slow wave detection was made using this instrument (repeating and improving the original work on the slow modes will be the first part of our data analysis). Previous observational results also provide some tantalising suggestions that Alfven and fast modes are supported in polar plumes. The observations of DeForest et al. (1997) hinted of a ripply appearance (sub-resolution behaviour of the propagating fast kink wave) and there is indirect spectral evidence for the (unresolved) presence of Alfven waves (O'Shea et al. 2003). Finally, we have never before had the overlap of such unique and high-resolution observations and we now have the full suite of instruments necessary to address all of our scientific aims. In addition, plumes are most clearly observed at solar minimum, and right now the Sun is in one of the deepest ever recorded minima, which we believe makes the timing of this HOP/JOP proposal ideal. References ---------- DeForest et al. (1997) Sol. Phys., 175, 393 DeForest & Gurman (1998) ApJL, 501, L217 O'Shea et al. (2003) A&A, 400, 1070 Raouafi et al. (2008) ApJL, 682, L137 Pointing & Target Selection --------------------------- The south or north coronal hole, with preference given to the coronal hole that has the larger spatial extent. However, the primary aim of this HOP/JOP is to observe polar plumes and so, above all else, the target coronal hole must contain a target polar plume. Proposed Observation Dates -------------------------- The south coronal hole will be slightly more tilted towards Earth in February and March. Thus, if there exists a south coronal hole that also contains plumes in February or March, then this would be an ideal observing time. Apart from this, then anytime would be acceptable, only noting that it is only during solar minimum that we can clearly observe plumes in fully developed coronal holes and, since the Sun is currently in one of the deepest recorded minima, that the timing right now is ideal. [1] NOTE on scheduling Hinode: HOP 98 is scheduled to run 27/28 February 09 (for the first time), subject to availability of a suitable target plume. [2] NOTE on scheduling CDS: When scheduling with Hinode, we request dates outside SOHO 'keyholes' during which CDS has very little observing time and so cannot promise support. For 2009, these dates are: -------------------------------------------------------------------------- 2009 24-Jan-09 31-Jan-09 15-Feb-09 22-Feb-09 27-Apr-09 01-May-09 13-May-09 17-May-09 21-Jul-09 28-Jul-09 14-Aug-09 21-Aug-09 26-Oct-09 30-Oct-09 10-Nov-09 14-Nov-09 -------------------------------------------------------------------------- [3] NOTE on scheduling STEREO/EUVI: Please run the JOP/HOP before mid-May 2009. The STEREO telemetry rate decreases at that time, as the spacecraft get further from Earth. After this time, it may not be possible to run the high cadence portion of the observations. [4] NOTE on scheduling TRACE: From Karel Schrijver: "TRACE no longer can observe without interruptions: every orbit there is now an eclipse (and somewhat period of atmospheric absorption) lasting from 10 to 20 min. Feb. and March are relatively good months with fairly short eclipses. Look at the orbits once you have dates scheduled to optimize when to schedule the high-cadence window of your plan. In addition, part of TRACE's orbits go through the SAA for about an 8h period each day. The high-cadence campaign segment should be scheduled outside those times (i.e., roughly outside the period and ideally between 0UT and 6UT)." [5] NOTE on scheduling TRACE with HINODE: From Ted Tarbell: “Tom & I both looked at this proposal from the Hinode point of view. TRACE has an SAA-free period of roughly 0-6 UT, and a nearly SAA-free period of roughly 12-16 UT. Hinode has an SAA-free period of roughly 11-16 UT and a period with very short SAA's of roughly 23 - 2 UT. TRACE has slightly better telemetry coverage in the earlier period; with Hinode, that's not an issue. So in choosing the time of day, consider the relative importance of SAA-free time for TRACE vs. Hinode EIS & XRT. SOT isn't much affected by SAA.” Specific Instrument Requirements -------------------------------- Assuming campaign starts at 00:00 UT, then campaign consists of “lifetime campaign” from 00:00 UT - 06:00 UT, then “high cadence campaign” from 06:00 UT - 08:00 UT, then resumes “lifetime campaign” from 08:00 UT - 08:00 UT following day. At 08:00 UT following day, the JOP/HOP ends. Total observing time = 32 hours. Lifetime Campaign (6 hours before and 24 hours after high cadence campaign, e.g. Assuming campaign starts at 00:00 UT, then lifetime campaign is 00:00 UT - 06:00 UT, then resumes 08:00 UT - 08:00 UT following day) ----------------- ----------------- Hinode/SOT NFI: Na I D IVDG mode (Stokes I, Stokes V, and dopplergrams), line-center tuning, 2k x 2k (110" x 110") 2x2 summed, cadence 5 minutes. SP: three Fast map 120" x 164", one taken every two hours (assuming lifetime campaign starts at 00:00UT, then the three fast maps should be taken at 00:00 UT, then 02:00 UT, then 04:00 UT. ***************************** NOTE 1: If additional memory is needed to fit in the SP Fast map at 06:00 UT (see high cadence campaign below), then drop the earlier SP map at 00:00 UT. NOTE 2: After 08:00 UT, the lifetime campaign resumes. If data allocation allows, then: NFI: Na I D IVDG mode (Stokes I, Stokes V, and dopplergrams), line-center tuning, 4k x 2k (220" x 110") 2x2 summed, cadence 5 minutes. **************************** Hinode/XRT Sub-field 512x512". Al_poly, 16 sec exposure time, 1.02086 spatial resolution, cadence 10 minutes SOHO/EIT Normal synoptic programme STEREO/EUVI Normal synoptic campaign TRACE 171 A images, 512 x 512 fov, 1" pixels. Cadence 10 minutes, 70 sec exposure time High Cadence Campaign (2 hours, i.e. assuming lifetime campaign starts at 00:00 UT, then high cadence campaign is 06:00 UT – 08:00 UT) --------------------- --------------------- Hinode/EIS: Context raster should point at coronal polar hole with target plume central in fov. Target plume will be chosen by James McLaughlin (i.e. he will choose a “nice” target plume. If not possible, then please choose a "nice" target plume yourselves. Same one as CDS please!). Plume footpoints must be in fov - and as much of the plume length as possible should be observed. Run sta_plume_context, once at start of observation before 2 hour high cadence observations 4/5 repeats of sta_plume_slot, to fill 2 hour high cadence period Run sta_plume_context, at end of observation after 2 hour high cadence period sta_plume_slot. Area 40x512", 4" slot, exposure time 30 seconds, number of repeats 50, cadence 28 minutes, 16 seconds, compression jpeg 75, data rate 17.2982 kbits/s, data volume 29333.33 kbits, emission lines Fe XI (188.23), Ca XVII (192.82), Fe XII (195.12), Fe XIII (202.04), Fe XIII (203.83), He II (256.32), Fe XVI (262.98), Mg VI (269.00), Fe XIV (274.20), Si VII (275.35), Fe XV (284.16) sta_plume_context. Area of raster 120x512", 2" slit, locations per raster 60, step size 2", exposure time per step 60 seconds, cadence 1 hour 5 minutes 20 seconds, compression DPCM, data rate 12.2949 kbits/s, data volume 48200.84 kbits, emission lines Fe XII (186.75), Fe XI (188.23), O V (192.90), Fe XII (195.12), Fe XIII (202.04), Fe XIII (203.83), He II (256.32), Fe XIV (274.20), Fe XV (284.16) Hinode/SOT: BFI: Ca II H-line 2k x 2k (110" x 110") 2x2 summed, spatial resolution 0.22", exposure time 500 milliseconds , cadence 10 seconds. SP: one Fast map 120" x 164" at 06:00 UT (i.e. Make one vector magnetogram raster with spectro-polarimeter at beginning of high cadence observations). ***************************** NOTE 3: If additional memory is needed to fit in the SP Fast map at 06:00 UT, then drop the earlier SP map at 00:00 UT. **************************** Hinode/XRT: Sub-field 512x512". Al_poly, 16 sec exposure time, 1.02086 spatial resolution, 30 second cadence SOHO/CDS: Context raster should point to polar coronal hole. Footpoints of plumes must be included in field-of-view, and as much of the plume length must be covered. Target plume will be chosen by James McLaughlin (i.e. he will choose a “nice” target plume. If not possible, then please choose a "nice" target plume yourselves. Same one as EIS please!). Start with EJECT_V3/v18 context raster Follow with SAS250W/v14 Finish with EJECT_V3/v18 context raster EJECT_V3 raster. Raster area 4x4 arcminutes, slit, 4x240 arcsecond, locations per raster 60, step size 4 arcseconds, exposure time per step 10 seconds, wavelengths Si X 347.400 (1.2 MK, density), He I 584.33 A (0.02 MK), Si X 356.040 (1.2 MK, density), Fe XVI 360.760 A (2.5 MK), Mg IX 368.060 A (1 MK), O V 629.73 A (0.25 MK), cadence 16m 10 seconds. SAS250W/v14. 4 x 240" slit, 250 repeats (Note: no summing in y). Exposure time 30 seconds. SOHO/EIT: Subfield 416x416 FOV, 2" arcsecond spatial resolution, 171 A 68-69 second cadence. STEREO/EUVI: Partial field (strip 2048 x 512 covering target coronal hole), 30 second cadence, 171 A (4-10 second exposure time), 1.6 arcsecond spatial resolution, ICER 6 compression. Means turning off COR1 and COR2. TRACE: 171 A images. Area: 512 x 512 at 1.0''. Cadence: 30 sec, with an exposure time very close to that, i.e. The best you can do. 2x2 binning. We also request "lossless" compression (so that we have the option of co-adding images at a later date).