Planning Flare Observations for Hinode/EIS Ryan Milligan NASA/GSFC
EUV Imaging Spectrometer (EIS) CDS Exposure times 1s 10s Raster cadence 3 mins 11 mins FOV 512"x360" 240"x240" Temp range 0.1-20 MK 0.01-10 MK Doppler resolution 3 km/s 15 km/s Spatial resolution 1 arcsec 4 arcsec
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 Exposure times 1-30 seconds Raster or ‘sit and stare’ Field of view Up to 512"x256"
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%)
CAM_ARTB_RHESSI_b_2 40143 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
RHESSI 19-25 keV
RHESSI 19-25 keV
Velocity vs. Temperature
Max Millennium Major Flare Watch SOHO/CDS Hinode/EIS ? 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.
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.
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.
EIS flare observations require large data volumes 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
GOES lightcurve with RHESSI and Hinode orbits
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?
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? …
Outline Introducing EIS… Creating EIS studies Chromospheric Evaporation using EIS Outstanding questions on solar flares The X-band problem