Science Specification of SOLAR-C payload

SOLAR-C Working Group2012 July 23

SUVITItem DescriptionTelescope Aplanatic Gregorian telescope: diameter of primary: ~1.5m

Focal Plane Instruments Broadband Filtergraph (BF), Narrowband Filtergraph (NF), Spectro-polarimeter (SP)

Wavelength coverage 280 nm (TBD) – 1100 nm

Spectral lines (spectro-polarimetry)

Chromosphere: He I 1083 nm, Ca II 854 nm Dynamics: Mg II 280nm (not baseline)Photosphere: Si I 1082.7 nm, Fe I 525 nm

Spectral lines (imaging)

Chromosphere: Mg II 280nm (TBD), Ca II 854nm, H I 656nm, Na I 589nm, Mg I 517nmPhotosphere: Fe I 525 nm, continuum (wavelength TBD)

Sampling scale Imaging: 0.015” (narrow field), 0.045” (wide field)Spectro-polarimetry: 0.07”

Spatial resolution (or imaging performance)

Imaging: 0.05” at 280nm (TBD), 0.09” at 525nm, 0.14” at 854nmSpectro-polarimetry: Slit scan: 0.14”, IFU: 0.14”(along slit)×0.18” (across slit)

Slit width Slit: 0.07”, IFU: effectively 0.18”

Spectral resolution Narrowband filtergram: ~50,000Spectro-polarimetry: 100,000 –210,000 (slit), ~96,000 (IFU)

Exposure time Intensity observations: 0.05 – 1 sec, Polarimetric observations: 1 – 20 sec

Polarimetric accuracy of chromospheric lines

1×10-4 (6×10-3) for 0.2” (0.1”) sampling and 20 (1) sec integration Sensitivity of Blong: 1–2 (10-20) G, of Btrans: ~100 (~300G) [Zeeman], 0.1–100 [Hanle] G

Filed of view Imaging: 61×61 arcsecs (narrow field), 184×184 arcsecs (wide field)Slit scanning polarimetry: 184×143 arcsecs2D spectro-polarimetry (IFU) : 10×10 arcsecs

SUVITItem Science requirements Science

backgroundsRelated hardware limitations

1.5m telescope aperture - High spatial resolution <0.1”- Number of collected photons for

spectro-polarimetry of chromosphere

- Signature of smaller-scale photospheric/chromospheric structures in Hinode observations and recent numerical simulations

- 0.01% polarization measurement for chromospheric magnetic fields

- Fairing size of H IIA rocket- Max size of 1.5m diameter mirror

available from the mirror vendor that has Hinode heritage

0.015” (0.045”) spatial sampling in imaging observations

- Diffraction limit of 1.5m telescope at 280nm: 0.047”

- (FOV=184”x184”)

- Highest resolution in UV range

- (FOV to cover typical active regions)

- Pointing stability by active controls- Optical performance and image

restoration at UV

Slit width - Slit scan 0.07”- IFU: 0.18”

Optimized for IR observations in spatial resolution and throughput

- Format of detector for target FOV- Available optical fibers for IFU

Line selection (spectro-polarimetry)

- He I 1083nm, Ca II 854nm- Mg II 280nm (TBD)- Fe I 525 nm (TBD)

- Measurement of chromospheric magnetic fields and dynamics

- Measurement of photospheric magnetic fields and dynamic

- Detector sensitivity at visible and near-IR

- Simultaneous observation of two wave bands not possible

- Mirror coating and glass materials for sensitivity at UV

Spectral resolution - Slit: 100,000 – 200,000- IFU: 96,000

- Sufficient for both photosphere and chromosphere

- IFU: sufficient for chromosphere

- Detector format in association with observing spectral range and FOV

- Available optical fiber for IFU

Exposure duration Intensity: < 0.05–1 secPolarimetry: 1–20 sec

- High-frequency waves- 0.01% photometry for B

- High-speed IR camera- Limited temporal cadence or

duration because of the limited telemetry amount

Field of view 184×184 arcsecsRaster scan 184×143 arcsecs IFU: 10×10 arcsecs

- Diffraction limit, wide field- Size of active regions- Size of chromospheric structures

- Sampling unit and detector format- Optical design to accommodate

large FOV.

EUVS/LEMURItem DescriptionTelescope Off-axis single mirror telescope: diameter of primary: 30 cm

Focal Plane Instruments Spectrographs, Slit imaging camera for co-alignment

Wavelength coverage Spectrographs: First order: 17–21 nm, 69 – 85 nm, 92.5 – 108.5 nm, 111.5–127.5 nm Second order: 46–54 nm, 56–64 nm Slit imaging camera: A chromospheric line/band (e.g., continuum around 160 nm)

Temperature coverage 0.01 – 20 MK

Imaging performance 0.28″ in 80% encircled energy over nominal field of view (FOV) (0.14″ reachable in the 17-21 range on a reduced FOV)

Spatial sampling 0.14” at detector

Slit 0.14″, 0.28″, 0.56″, 1″, 5″

Spectral resolution ( / ) l Dl 17,000~30,000

Exposure time 1 – 5 s for 0.28 arcsec sampling 0.1 – 0.5 s for 1 arcsec sampling

Field of view 280 arcsec (along slit) × 300 arcsec (scanning direction)

EUVS/LEMURItem Science requirements Science backgrounds Related hardware

limitationsTelescope aperture 30 cm High sensitivity Primary mirror needs a fine

pointing capability (raster scanning and image stabilization)

Wavelength (or line) selection

Spectrographs: Fist order: 17–21 nm, 69 – 85 nm 92.5 – 108.5 nm, 111.5–127.5 nmSecond order: 46–54 nm, 56–64 nm

Slit imaging camera: Chromospheric image with 0.3″

Spectrographs: Make measurements with spectral lines from a broad temperature range and with adequate plasma diagnostics covering the entire outer atmosphere, i.e., chromospheric, transition region, low corona and flare temperatures. Because of the required high temporal and spatial resolution, the spectral bands were defined such to include intense spectral lines in all temperature regimes. Slit imaging camera: Co-alignment with other instruments

Spectrographs: - 17-21 nm band: CCD detector with aluminum foil filter for rejecting the visible light and with a focal plane shutter. - Other bands: Intensified CCD or APS detector (blind to visible light).

Spectral resolution (λ/Δλ)

17,000 ~30,000 Enhancement in velocity resolution for the unresolved velocity signature at the energy deposition sites in Hinode observations

- Instrument length < spacecraft- Minimum number of reflections- Temperature coverage has

higher priority than high spectral resolution.

Imaging performance 0.28″ in 80% encircled energy over nominal FOV(0.14″ achievable in the 17-21 nm band)

Typical width of chromospheric features is 0.3-0.4″. Coronal volume filling factor ~0.1 from Hinode observations at 2″ spatial resolution.

- Instrument length- TVLS grating magnification.- Image stabilization.

Exposure cadence - 1 – 5 s for 0.28″ sampling- < 1 s for 1″ sampling

- Rapid heating of coronal structures - Effective area (Size of primary mirror, reflectance, grating efficiency, detector efficiency)

Scanning cadence ~25 s for 14″ wide area (0.28″) ~500 s for 280″ wide area (0.58″)

- Local dynamics - Dynamics in active regions

- Readout speed of detector- Response time of mechanisms

Field of view Spectrographs: 280″ (along slit) ×300″ (scan range)Slit imaging camera:> 200″ ×300″

Full coverage of an active region

Co-alignment with other instruments

- 2K pixel detector along the slit- Scanning range - Image quality over FOV

XIT/GI

Item DescriptionTelescope Ritchey-Chretien telescope: diameter of aperture: ~30 cm

Focal plane detector Back-illuminated CCD

Wavelength range 9 – 34 nm (some from 9.4nm, 17.1nm, 19.5nm, 21.1nm, 30.4 nm, 33.5nm)

Plate scale 0.1 arcsec/pixel sampling

Spatial resolution 0.2 – 0.3 arcsec within 200 arcsec off-axis distance

Exposure cadence < 10 sec

Filed of view 400 arcsec × 400 arcsec

Item DescriptionTelescope Wolter-I telescope: diameter of aperture: ~25 cm

Focal plane detector Back-illuminated CMOS-APS

Energy range 0.5 – ~10 keV

Energy resolution ~150 eV at 5.9 keV

Plate scale 0.5 arcsec sampling

Spatial resolution 1.0 arcsec within 200” off-axis distance

Exposure cadence Photon integration mode: < 1 sec Photon counting mode: 10 (20) sec for 2” (1”) area

Filed of view Photon integration mode: 400 arcsec × 400 arcsecPhoton counting mode: ~80 arcsec × 400 arcsec (baseline) ~200 arcsec × 400 arcsec (goal; cover NS×EW extent of ARs)

XIT/NI

XIT(GI, NI)Item Science requirements Science

backgroundsRelated hardware limitations

Wavelength selection GI: soft X-rays 0.5 – 5 keV (baseline) 0.5 – 10 keV (goal)NI: some from 6 EUV bands

GI: revealing the site of heating in the coronaNI: image low corona as well as flare high temperature plasmas

GI: photon-counting possible in soft X-raysNI: contribution of many other lines

Wavelength resolution λ/Δλ

GI: ΔE ~ 150 eV

NI: λ/Δλ > 30

GI: obtain emission-line structure in energy spectrumNI: avoid confusion due to nearby emission lines

GI: available energy resolution of Si NI: resolution of multi-layers < 40

Spatial resolution GI: 1.0” (0.5” sampling)

NI: 0.2” (0.1” sampling)

GI: ~1/3 scale size of known flare structures near reconnection siteNI: coronal volume filling factor ~0.1 from Hinode observations of 2” spatial resolution

GI: telescope length < spacecraft

NI: trade between spatial resolution and wide field coverage

Field of view GI: - integration mode: 400×400 arcsec- ph-counting mode: 80×400 arcsecNI: 400×400 arcsec

GI & NI: Full coverage of an active region

GI: - APS detector format of 2K×2K and spatial sampling - on-board ph-counting speed NI: CCD format of 4K×4K and spatial sampling

Exposure cadence GI: ph-integration mode < 1 sec ph-counting mode 10 (20) sec for 2” (1”) areaNI: < 10 sec

GI: rapid heating of coronal structures

NI: Faster cadence than LEMUR for providing context images

GI: - Effective area

NI: readout speed of 4K×4K (can be improved by CMOS) telemetry amount