1. SDO/AIA science plan: prioritization and implementation: Five Objectives in 10 steps C31 I: Session C3 Thermal Studies : Techniques Chair(s): Mark Weber & Paul Boerner Status: draft

2. C32 Guidelines to group leads Assess the task definitions in appendix A (‘AIA Science Plan’) in the 2004 Concept Study Report (CSR). In particular: Science/task descriptions in Ch. A1.1 Summaries in Table A2 Identify required changes from, and additions to, the ‘AIA Science Plan’ Evaluate the status of that plan, and formulate changes, if needed. You may add as many pages to this document as you need, but: Add pages under the same headings: please, do not change the roman numerals in the page titles, please add ‘a, b, c, d, …’ Resources: AIA home: http://aia.lmsal.com/http://aia.lmsal.com/ AIA CSR summary: http://aia.lmsal.com/public/CSR.htmhttp://aia.lmsal.com/public/CSR.htm CSR: https://aia.lmsal.com/doc?cmd=vcur&proj_num=AIA00435https://aia.lmsal.com/doc?cmd=vcur&proj_num=AIA00435 Proposal: https://aia.lmsal.com/doc?cmd=vcur&proj_num=AIA00341https://aia.lmsal.com/doc?cmd=vcur&proj_num=AIA00341

3. C33 Schedule 17 November 2005: draft sheets I, II to teams, requesting input for sheets III and IV 24 November 2005: completed sheets I-IV for review to teams, requesting input for sheets V-VI 8 December 2005: team input received for sheets V-VI 19 December 2005: draft of sheets VII-VIII to teams 9 January 2006: team comments received for sheets VII-VIII 6 February 2006: draft ‘Science plans’ on meeting website, with sheets IX-X filled out by team leads (or teams after telecons) 13-17 February 2006: discussions during science team meeting discuss and complete pages IX-X. 17 February: completed ‘Science plans’ on line.

4. C34 IIa: Science questions and tasks (from CSR) Primary scientific questions: Objective 2: Study coronal heating and irradiance, and the origins of the thermal structure and coronal emission, to understand the basic properties of the solar coronal plasma and field, and the spatially-resolved input to solar spectral irradiance. SDO/AIA science tasks: Task 2B: Characterize the physical properties of coronal structures

5. C35 IIb: Science questions and tasks (DEM recovery) DEM recovery offers a description of the thermal structure along a line of sight, which allows us to: distinguish overlapping structures in the optically- thin corona distinguish between plasma motion and heating identify the location and magnitude of heating and cooling events track plasma topology and connectivity relate morphology and dynamics observed in the corona with AIA to irradiance observed with EVE

6. C36 IIIa: Science context There are a number of upcoming advances that should leave us in a better position to do thermal studies when SDO launches than we are now: Observations with broader spectral (and thermal) coverage, particularly from SOLAR-B EIS and XRT; also GOES-N SXI, STEREO SECCHI Gradual improvements in spectral codes and databases Faster computers and larger displays, which will facilitate the computation and visualization of DEM data products Improvements in the software and techniques that enable the analytic combination of multiple instrument datasets (e.g. TRACE, MDI, EIT, CDS…)

7. C37 IIIb: Science context (cont.) SDO should advance our understanding of coronal thermal structure even further: AIA is designed for DEM recovery, with more EUV bandpasses than have ever been available from a high-resolution imager High spatial resolution is required in order to study the thermal properties of elemental structures High cadence allows studies of the evolution of coronal structures at the shortest relevant timescale

8. C38 IVa: Science investigation Uncertainties in spectral models are a major obstacle databases rely on tabulated measurements of abundance, ionization balance, etc., which may not be correct or constant spectral databases do not have complete catalogues of coronal emission lines Another major obstacle is the scaling of the computation difficult to compute, analyze and display DEMs for the whole volume of AIA observations

9. C39 IVb: Science investigation Additional obstacles: instability of DEM inversion in the presence of error and uncertainty range of possible DEM solutions and uniqueness of recovered DEM must be estimated and understood optical depth of plasma is difficult to accommodate in large scale, automated codes going from LOS DEM to a description of thermal structure in a volume element not always trivial

10. C310 V: Implementation: general In order to improve our ability to do useful thermal studies, we need: A DEM working group that will  foster a broader understanding of the need for, and difficulty of, DEM analysis  reach a consensus on many implementation issues Improvements to spectral models and databases These will allow us to work towards a standard DEM recovery code that will provide easily understood uncertainty estimates, temperature maps, and LOS discrimination

11. C311 VI: Implementation: AIA+HMI DEM inversion requires AIA observations: in all EUV bandpasses near-simultaneous Cadence of ~1 minute Full dynamic range (longest exposures possible without saturating) Simultaneous HMI observations to enable study of topology/connectivity requires co-alignment with AIA Simultaneous EVE observations for cross- calibration

12. C312 VII: AIA (+HMI+EVE) data products Critical data products: SDO data:  AIA observations in EUV bandpasses Desireable data products SDO data:  HMI observations of magnetic field  EVE observations for cross-calibration Supporting data from other observatories:  EIS spectra for cross-calibration  STEREO images to distinguish 3-D structure

13. C313 VIIIa: AIA (+HMI+EVE) data production Open question: should there be a DEM data product in the pipeline? computationally intensive  could implement linear inversion or lookup table numerous knobs must be set almost arbitrarily  parameterization of DEM (range, resolution in T space)  spectral code and assumptions (abundance, pressure, etc)  conduct DEM recovery study to optimize these settings difficult to include other observations in the pipeline

14. C314 VIIIb: AIA (+HMI+EVE) data production If we do have a standard DEM product, we will need to decide: how comprehensively it will be produced  full-disk, full-resolution per-pixel DEMs?  bin pixels, sum over multiple exposures  run DEM recovery routine selectively how to display the recovered DEM  temperature maps  error bars/level of certainty

15. C315 IXa: Business plan: Resources AIA can be used for thermal studies in 2 ways: for quicklook T maps, and for more careful/detailed DEM reconstruction. It would be useful to supply 2 DEM data/code products: A pipeline DEM/Temperature map data product; A set of software tools to allow expert users to perform DEM reconstruction

16. C316 IXb: Business plan: Resources The pipeline data product should: Be clear and usable by experts and non-experts Supply information that is not available in the standard images Allow users to identify features, events, and regions that warrant for further study The DEM reconstruction software package should allow users to: Tweak a variety of atomic parameters (abundance, charge state, etc.) and a priori constraints (smoothness, etc.) Include observations from other instruments, and from models Understand the uncertainties in the recovered DEM

17. C317 Xa: Business plan: Implementation Develop a “white paper” and work with people who calculate and measure atomic physics properties to reduce atomic uncertainties in the AIA bandpasses Hold workshops to develop an understanding of the problem of DEM reconstruction with AIA ~30 participants, incl. representatives of the instrument, spectral codes, and modeling teams Focused on DEM reconstruction problems (not spectral codes):  Inversion algorithms  Uncertainties  Data pipeline realities Preliminary meeting adjacent to SPD 2006; identify problems and have volunteers work on them Follow-up meeting in Feb 2007

18. C318 Xb: Business plan: Implementation The Pipeline Product: Do we need a DEM data product in the pipeline? This fundamental question is still unanswered Survey community to determine how it would be used, and how useful it would be (May 2006) Based on the study of how practical DEM reconstruction is (see Xa), develop and test methods to determine how it could be implemented (Early-mid 2007)  Spatial resolution (number of DEM pixels)  Inversion technique  Standard set of “atomic physics” assumptions