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Planning Flare Observations for Hinode/EIS

Planning Flare Observations for Hinode/EIS. Ryan Milligan NASA/GSFC. EUV Imaging Spectrometer (EIS). Rastering. Observing Study Selection. Line selection Short wavelength channel: 170-211A Long wavelength channel: 246-292A Slits or slots 1" and 2" slits 40" and 260" slots

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Planning Flare Observations for Hinode/EIS

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  1. Planning Flare Observations for Hinode/EIS Ryan Milligan NASA/GSFC

  2. EUV Imaging Spectrometer (EIS)

  3. Rastering

  4. Observing Study Selection • Line selection • Short wavelength channel: 170-211A • Long wavelength channel: 246-292A • Slits or slots • 1" and 2" slits • 40" and 260" slots • Exposure times • 1-30 seconds • Raster or ‘sit and stare’ • Field of view • Up to 512"x256"

  5. EIS studies • http://msslxr.mssl.ucl.ac.uk:8080/SolarB/EisStudyList.jsp • 325 studies (1-Dec-2008) • QS, AR, Flare, CH, Filament, Engineering • Only 5 of these are designed specifically for flares (1.5%)

  6. CAM_ARTB_RHESSI_b_2 • 40143 FOV • 4 minute raster cadence • 10 second exposure • Wide range of emission lines: • He II • O IV, V, VI • Mg V, VI, VII • Si X (density sensitive pair) • Ca XVII • Fe VIII, X, XI, XII, XIII, XIV, XV, XVI, XVII, XXIII, XXIV

  7. RHESSI 19-25 keV

  8. RHESSI 19-25 keV

  9. Velocity vs. Temperature

  10. Hinode/EIS ? Max Millennium Major Flare Watch SOHO/CDS • ACTIVITY: To be run with TRACE/EIT/MDI/RHESSI. Continuous tracking of a flare-producing active region. When an active region has a high probability of producing a large flare, a Major Flare Watch is likely to be called by the RHESSI team. As much time as possible should be devoted to the flare watch. • STUDIES TO BE RUN: Begin with one ARDIAG_2 (ID 11 , var. 98), and follow with many FLARE_AR (Study ID 173, var 9), 3x3 arcmin field. Follow with solar rotation, modifying the pointing once per hour (or when the pointing change is approx. 10 arcsec). Repeat FLARE_AR for several hours. If short of time, run only FLARE_AR. • POINTING: Pointing coordinates are sent out each day by the Max Millennium team. The CDS planner receives these e-mails. • DURATION: A few hours per day, when run. It may be continued for longer if the flare activity and chances of recording a flare are high.

  11. X-band downlink problem • At the end of 2007, X-band transmitter signal began to experience irregularities in the latter half of each contact with the ground station. • Irregular signal has caused partial and complete loss of science telemetry data. • Primary downlink path was switched to S-band transmitter in March 2008 • 256 Kbps, instead of 4 Mbps with X-band.

  12. Current telemetry restrictions • Telemetry divided between 3 instruments • SOT 70%, XRT 15%, EIS 15% • Telemetry volume reduced to 20-50% after X-band problem • For EIS currently ~500 Mbits per day.

  13. EIS flare observations require large data volumes. Sample study: CAM_ARTB_RHESSI • 21 windows, 40”x140” FOV, 4 minute cadence, no comp. • Datarate of 58 Kbps, could be run for 2.5 hours!! • Possible solutions for running similar study during high activity periods (>12 hours per day) • Need to ‘borrow’ SOT telemetry • More ground stations coming online • Reduce number of lines, cadence, FOV, etc. • Data buffering - overwrite non-flaring data • Compress data

  14. GOES lightcurve with RHESSI and Hinode orbits

  15. Generic Study • FOV: 80”x120” Comparable to moderate sized AR • Raster cadence: < 5 minutes • Exposure times: 5 seconds • Line selection: • Fe X, Fe XII, Fe XV, Fe XXIII, Fe XXIV • Density sensitive lines • Need Target Of Opportunity • Track active region for > 12 hours per day • Flare trigger mode may miss impulsive phase • Study must be science-driven • What are the outstanding issues? • How can EIS be used to answer them?

  16. Outstanding Issues… • How does emissivity of upflowing material vary w.r.t. velocity and temperature (VDEM)? • Momentum balance between up- and downflowing material • Upflow velocity as a function of time • beam driven versus conduction driven? • How do electron beam parameters affect the evaporation process? • Density variations/enhancements using line ratio techniques • Thermal/nonthermal line broadening • Why are the hottest lines predominantly stationary? • Reconnection inflows? Coincident with coronal HXRs? • …

  17. Outline • Introducing EIS… • Creating EIS studies • Chromospheric Evaporation using EIS • Outstanding questions on solar flares • The X-band problem

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