000509EISPDR_SciInvGIs.1

EIS Performance and Operations

Louise Harra

Mullard Space Science Laboratory

University College London

The 2nd Solar B Science Meeting 4-6 Dec 2000

Extreme-Ultraviolet Imaging Spectrometer (EIS)

• EIS Records Solar Extreme-Ultraviolet (EUV) Spectra That Contain Information on the Dynamics, Velocity, Temperature, and Density of the Emitting Plasma

• Spectra Are Obtained With High Spatial Resolution

– Spectra at Many Locations Within an Entire Solar Structure Can Be Recorded

• Spectra Are Obtained With Sufficient Time Resolution to Determine the Dynamics As a Function of Position Within Solar Flare and Active Region Loops

• Spectra Can Be Accurately Related to the Images Obtained From the Solar-B White Light and X-Ray Telescopes

• EIS Is the First EUV Solar Spectrometer Capable of Obtaining High Spectral Resolution Data With Both High Spatial and Temporal Resolution

The 2nd Solar B Science Meeting 4-6 Dec 2000

Simplified Schematic of EISSimplified Schematicof the EIS Instrument

SunFilter

GratingPrimary

CCD Long

CCD Short

Slit

Simplified Schematic of the

EIS Instrument

Filter

The 2nd Solar B Science Meeting 4-6 Dec 2000

• Perform:

• EUV Spectroscopy with High Spectral and Spatial Resolution

• Monochromatic EUV Imaging

• Imaging and Spectroscopy with High Temporal Resolution

• Obtain:

• Imaging and Spectral Measurements from Lines in Transition Region, Coronal and Solar Flare Plasma

• Accurate Coronal Density Measurements

• Respond to Highly Dynamic Phenomena

• Locate and Change the Observing Mode to a Region of Brighter Intensity

• Observe a Range of Sizes of Solar Phenomena

Summary of Science Requirements

The 2nd Solar B Science Meeting 4-6 Dec 2000

Temperature coverage

• A temperature range of 0.1MK to 20 MK is required (transition region, corona and solar flares).

• Need observations in the EUV

• Wavelength bands chosen are 170-210 A and 250-290 A.

• This also includes the density sensitive lines to measure densities between 108 cm-3 and 1012 cm-3.

The 2nd Solar B Science Meeting 4-6 Dec 2000

Spectral resolution

• High spectral resolution required - need to determine Doppler vels of ~3 km/s and a line width measurement down to 20 km/s.

• This is achieved by having a spectral resolution of 0.0223 A and a high throughput (e.g 1000s cts/s in flares, 100s cts/s in active regions).

The 2nd Solar B Science Meeting 4-6 Dec 2000

Time resolution

• High temporal resolution is required in both imaging and spectroscopy mode - in flares need <1s, and in active regions 10 s.

• 50 ms exposure time is possible

• The spacecraft stability is 1.1” in 20 s

The 2nd Solar B Science Meeting 4-6 Dec 2000

Quiet Region Count Rates

Ion Wave T Incident Detected

Short Wavelength Band

Fe X 184.54 6.00 15.55 1.27

Fe XII 186.88 6.11 6.76 1.06

Fe XI 188.23 6.11 17.66 3.68

Fe XI 188.30 6.11 6.46 1.36

Fe X 190.04 6.00 4.86 1.36

Fe XII 192.39 6.11 7.54 2.71

Fe XI 192.83 6.11 3.78 1.40

Fe XII 193.52 6.11 20.57 7.95

Fe XII 195.12 6.11 34.29 13.82

Fe XII 196.65 6.11 3.03 1.17

Fe XIII 202.04 6.20 14.12 1.74

Long Wavelength Band

He II 256.32 4.70 63.18 4.74

Si X 258.37 6.11 12.47 1.00

Si VII 275.35 5.80 17.40 1.23

The 2nd Solar B Science Meeting 4-6 Dec 2000

Quiet Region Performance

The 2nd Solar B Science Meeting 4-6 Dec 2000

Active Region Count Rates

Ion Wave T Incident Detected Short Wavelength Band

Fe XI 180.41 6.11 690.49 14.62 Fe X 184.54 6.00 286.53 23.47 Fe XII 186.85 6.11 142.80 22.20 Fe XII 186.88 6.11 233.69 36.61 Fe XI 188.23 6.11 359.34 74.79 Fe XI 188.30 6.11 131.76 27.77 Fe X 190.04 6.00 89.48 24.95 S XI 191.27 6.20 31.00 10.04 Fe XXIV 192.04 7.30 39.46 13.78 Fe XII 192.39 6.11 233.45 83.94 Ca XVII 192.82 6.70 154.30 57.24 Fe XI 192.83 6.11 76.80 28.51 Fe XII 193.52 6.11 631.78 244.11 Ca XIV 193.87 6.51 41.57 16.31 Fe XII 195.12 6.11 1052.18 424.08 Fe XII 195.13 6.11 67.64 27.26 Fe XIII 196.54 6.20 86.19 33.58 Fe XII 196.65 6.11 105.45 40.83 Fe XIII 197.43 6.20 45.80 16.67 Fe XIII 200.02 6.20 155.95 36.00 Fe XIII 201.13 6.20 192.59 32.15 Fe XIII 202.04 6.20 591.85 72.96 Fe XIII 203.80 6.20 208.79 15.09

The 2nd Solar B Science Meeting 4-6 Dec 2000

Active Region Performance

The 2nd Solar B Science Meeting 4-6 Dec 2000

Flare Count Rates

Ion Wave T Incident Detected Short Wavelength Band

Fe XII 186.85 6.11 1179.01 183.27 Fe XII 186.88 6.11 1453.80 227.74 Fe XXI 187.89 7.00 3194.12 622.36 Fe XI 188.23 6.11 958.24 199.44 Fe XII 191.05 6.11 554.27 175.39 Fe XXIV 192.04 7.30 207852.89 72582.53 Fe XII 192.39 6.11 608.29 218.71 Ca XVII 192.82 6.70 8948.24 3319.59 O V 192.90 5.40 554.27 206.79 Fe XII 193.52 6.11 1425.61 550.84 Ca XIV 193.87 6.51 655.27 257.04 Ar XIV 194.39 6.51 256.00 102.10 Fe XII 195.12 6.11 2346.27 945.67 Fe XII 195.13 6.11 580.11 233.82 Fe XIII 196.54 6.20 1777.91 692.66 Fe XII 196.65 6.11 697.54 270.06 Fe XIII 200.02 6.20 897.17 207.10 Ca XV 200.98 6.60 634.13 111.05 Fe XIII 201.13 6.20 901.87 150.57 Fe XIII 202.04 6.20 1376.29 169.67 Fe XIII 203.83 6.20 3593.39 257.60

The 2nd Solar B Science Meeting 4-6 Dec 2000

Flare Performance

The 2nd Solar B Science Meeting 4-6 Dec 2000

a) Select a slit or slot as required. Four slit positions are available.

1" for optimum spatial sampling, a 40" slot for monochromatic imaging with no blending of stronger lines, a 2” slit for fastest time cadence, and >100” slit for spectroheliograms.

b) Point EIS in the E-W direction with a coarse pointing in the range +/- 15' with an accuracy of +/- 3". The coarse pointing will be used for approximate pointing to targets.

c) Fine pointing in the range 0 - 8 arc min.

d) EIS FOV is 480" x 512" (480" is the fine pointing range - set by optical aberrations, and 512" is the maximum image height on the CCD).

e) Stability during an observation of 1" in 10 s (the average exposure time for observation of an active region loop).

Spacecraft 3 stability is 0.5” in 2s, 1.1” in 20s and 1.7” in 1 min.

f) Determine EIS pointing with a fine pointing accuracy of 0.5". It is required to point

EIS with accuracy greater than the spatial resolution of 2”.

Instrument Design Requirements - Pointing and Field of View

The 2nd Solar B Science Meeting 4-6 Dec 2000

a) Expose and readout the maximum image area of both CCDs (2048 x 512 pixels) This facility is expected to be used for instrument health diagnostic purposes

b) Allow any fraction of the CCD slit length to be downloaded in the spatial direction. This is to allow the observation of a smaller FOV

c) Allow fractions of the CCD to be downloaded in the spectral direction - spectral windowing

d) Minimum of 1 spectral window and a maximum of 25 spectral windows.

Instrument Design Requirements - Data Readout Issues

The 2nd Solar B Science Meeting 4-6 Dec 2000

e) Expose and process 1 x 512 arc sec spatial sample (e.g. including readout time, compression) data in < 1s. f) Allow exposure times in the range 100 ms - 300 s with an accuracy of 5 %. The ability to make shorter exposures, down to 50 ms with reduced accuracy, is desirable.

g) Perform automatic exposure control.

h) Perform data compression. The data compression is currently JPEG in the MDP, but the facility to include a different compression scheme e.g. H-compress, in the ICU should remain open. It is required that the compression factor can be varied for different studies

Instrument Design Requirements - Data Readout Issues (Cont.)

The 2nd Solar B Science Meeting 4-6 Dec 2000

a) Science operations shall be configured from ground command.

b) The onboard software shall be designed to aid code development and to facilitate the uplinking of new software.

c) The study sequences shall consist of a number of variables (e.g. exposure time, number of spectral windows, spectral window width, slit/slot size, mirror step).

The variables should not be constrained so that for example different width values in the spectral window width can be different for each spectral line.

d ) The instrument shall also collect data based on a number of uplinked observing sequences.

e) The parameters (e.g. slit size, y size, exposure time) of the observation shall be changeable by command.

Instrument Design Requirements - Mode of Observation

The 2nd Solar B Science Meeting 4-6 Dec 2000

a) EIS shall be capable of responding (or not) to the Solar-B XRT Flare Trigger by moving its slit field of view to the flare location and starting a new observation sequence

Response shall only be if the flare is within the EIS fine field of view

b) EIS shall be capable of generating an internal Solar Event trigger

Response should include repositioning the slit field of view and changing the study in progress

c) EIS is required to locate regions of interest (e.g. bright points) within a raster or image.

It is then necessary to repoint to the ROI and change the study mode (e.g. FOV)

Instrument Design Requirements - Event Triggers

The 2nd Solar B Science Meeting 4-6 Dec 2000

Flare

The 2nd Solar B Science Meeting 4-6 Dec 2000

a) EIS shall have the ability to interrupt studies in progress - abort or pause and restart

b) EIS shall be capable of monitoring instrument health and entering a safe mode if an anomaly is detected

c) The instrument will be designed to respond in an appropriate manner to spacecraft emergencies

Instrument Design Requirements - Instrument Health

The 2nd Solar B Science Meeting 4-6 Dec 2000

Operations

• We plan to observe targets for long periods of time e.g. tracking an active region.

• We want to maximise the observing time with SOT/XRT.

• Periodically, we will wish to look at active regions/prominences/plumes at the limb.

The 2nd Solar B Science Meeting 4-6 Dec 2000

Information

• For producing sample observing studies go to; http:\\www.mssl.ucl.ac.uk\www_solar\solar-b\eistudyform.html

• For information on CCD readout go to;

• For general EIS information go to; http:\\www.mssl.ucl.ac.uk\solar-b

• For the science requirements document go to;http:\\www.mssl.ucl.ac.uk\solar-b\docs\doclist.html

• For any further information contact lkh@mssl.ucl.ac.uk