18-April-2006XRT Team1 Initial Science Observations Solar-B XRT Ed DeLuca for the XRT Team.

18-April-2006 XRT Team 1

Initial Science Observations

Solar-B XRT

Ed DeLuca for the XRT Team


XRT Instrumentation

• X-Ray Telescope– Mirror inner diameter: 35 cm– Focal Length: 2700 cm– Geometric Area: 5 cm2

• Shutter/Analysis Filters– exp: 2ms to 10s– 9 X-ray, 1 WL filter

• Camera– 2K2K back-illuminated CCD– 1 arcsec pixels (13.5m)


XRT Components


Optical PathX-Ray Mirror Shutter & filter

wheels

Visible Light Optic

Focus Mechanism


Grazing Incidence Mirror


Focal Plane Filter Wheels


Analysis Filter Set

FILTERMaterial Thickness Material Thickness Material

( Å) or % Trns. Front BackEntrance: Al Polyimide Al 1200 Polyimide 2500 Al2O3 75 25

Focal Plane: Thin Al Mesh Al 1600 Mesh 82% Al2O3 75 75 Al Polyimide Al 1600 Polyimide 2500 Al2O3 75 25

C Polyimide C 7000 Polyimide 2500 0 0 Ti Polyimide Ti 3000 Polyimide 2500 TiO2 75 25

Thin Be Be 9um - 100% BeO 75 75

Medium Al Al 12.5um - 100% Al2O3 75 75Medium Be Be 30um - 100% BeO 75 75

Thick Be Be 300um - 100% BeO 75 75Thick Al Al 25um - 100% Al2O3 75 75

White Light SiO2 2.5mm

Oxide LayersBackingThickness (A)


The XRT “Firsts”

1. Unprecedented combination of spatial resolution, field of view, and image cadence.

2. Broadest temperature coverage of any coronal imager to date.

3. High data rate for observing rapid changes in topology and temperature structure.

4. Extremely large dynamic range to detect entire corona, from coronal holes to X-flares.

5. Flare buffer, large onboard storage, and high downlink rate provide unique observing capability.

New XRT Instrumental Capabilities:


Observational Constraints

Our science program can be addressed by three basic types of XRT observations. These must be optimized subject to our data rate (~ 0.5 Gbyte/day - assuming 15 contacts, 8min/contact, 15% allocation)

• Thermal structure & energetics– 3-7 filters used per target region– May limit cadence or FOV to stay within the data rate.

• Dynamics– Fast cadence with 1 or 2 filters– May limit context images or FOV to stay within the data

rate

• Morphology / Topology– Large FOV, combine long and short exposures– May limit number of filters, cadence or FOV


XRT Initial ObservationsBasic Philosophy:Start simple, have a written plan before starting, stick to the plan

– Disk center• All filters, AEC tests, cadence, compression …• White light images with VLI -

– Check stability over orbit – Develop aspect calibration

• Limited flare response– Track a region

• Follow a region for several days (disk passage)• Explore different filter combinations• Verify aspect solution as SC position wrt the sun changes • Limited flare response

– Quiet sun studies• X-ray bright points• Coronal holes• Polar investigations• Limited flare response

– Baseline 15 ground contacts/day


Early Science Operations

Assume a modest AR on disk

• Follow AR across disk– Large FOV images with all filters - very limited

cadence (1536x1536, ~900 images/day, 1-2 days)– Medium FOV images with two filters plus context

(1024x1024, ~2000 images/day, 1-2 days)– Small FOV images one filter plus context (768x768,

~3600 image/day, 1-2 days)– High cadence on filter small fov, selected for short

exposure time (512x512, 3sec cadence, 8200 images, combine with low data rate program, 1-2 days)



Assume a dynamic AR on disk• Flare buffer check, set flare trigger at low

level, single filter response with high cadence (512x512),

• Follow AR across disk, flare program loaded– Large FOV images with all filters - very limited

cadence (1536x1536, ~900 images/day, 1-2 days)– Medium FOV images with two filters plus context

(1024x1024, ~2000 images/day, 1-2 days)– Small FOV images one filter plus context (768x768,

~3600 image/day, 1-2 days)– High cadence on filter small fov, selected for short

exposure time (512x512, 3sec cadence, 8200 images, combine with low data rate program 1-2 days)



Assume no AR on disk• Large FOV images with 3-5 filters - very limited

cadence (1536x1536, ~900 images/day, 1-2 days)

• Coronal Hole on Disk?– Track evolution of boundary, select a single filter that

images the plasma near the boundary well. (1024x1024, ~2000 images/day). Move SC pointing to image different parts of CH boundary with SOT. (3-5 days)

• Filament on Disk?– Track filament for 1-2 days. Long exposures in 1 or

filters to show magnetic structure around filament (1024x1024, ~2000 images/day).



Assume no AR on disk• XBP

– Thermal structure - Multi-filter study of bright points (1024x1024, ~2000 images/day). Do different filters show different structure? (1-2 days)

– Dynamics - one or two filters limited FOV track existing XBP to end of life (512x512, ~8200 images/day, 2-day continuous)

– Statistics - life cycle of multiple XBPs. One or two filters (1536x1536, ~900 images/day) track center of FOV for 3-4 days.


XRT Science Goals

1. Coronal Mass Ejections2. Coronal Heating3. Reconnection and Jets4. Flare Energetics5. Photospheric-Corona

Coupling


• Flares & Coronal Mass Ejections. – How are they triggered, and what is their relation to the numerous

small eruptions near emerging flux regions? – Flare Onset Program - Carbon or Thin Be filter, 3s cadence,

(512”x512”); Al-Poly, Thin Be or Carbon, Med. Be, 40s context, (1024”x1024”). Use Flare buffer.

– CME over the solar-limb with wide FOV - (2048”x2048”) with 4”x4” resolution, Al-Poly, C, 1min cadence

– What is the relationship between large-scale instabilities and the dynamics of the small-scale magnetic field?

• Coronal heating mechanisms. – What is the thermal structure of AR loops?

– DEM - hi-res - Al-Poly, C, Thin Be, Med. Be, Med. Al, 60s cadence, (1024”x1024”).

– TRACE observes loop oscillations associated with flares (Nakariakov et al. 1999). Are other wave motions visible? Are they correlated with heating?

– Do loop-loop interactions contribute to the heating?

Critical science questions


• Reconnection & coronal dynamics. – Yohkoh observations of giant arches, jets, kinked and

twisted flux tubes, and microflares imply that reconnection plays a significant role in coronal dynamics. With higher spatial resolution and with improved temperature response, the XRT will help clarify the role of reconnection in the corona.

– Filament activation - Al-mesh, Al-poly, C, Thin Be, 60s cadence, (1024”x1024”).

• Solar flare energetics. – Although Solar-B will fly at solar minimum, there will still be flare

events seen. The XRT is designed so that it can test the reconnection hypothesis that has emerged from the Yohkoh data analysis.

• Photosphere/corona coupling. – Can a direct connection be established between events in

the photosphere and a coronal response? To what extent is coronal fine structure determined at the photosphere?

– XBP - one of (Al-p,C, Thin Be), 10s cadence, (768”x768”); 5 other filters (Al-p, C, Thin. Be, Med. Be, Med Al, Thick. Al), 120s cadence.

Critical science questions


Quiet SunCoronal

HoleX-ray

Bright PointPolar

FilamentEmerging

FluxActive Region

Isolated Sunspot

Active Region

FilamentDelta Spot

Polar Plumes

Spicules

Flare Onset X X

Flare Energetics X X

Flare Topology X X X XCME

AccelerationX X

Jet life cycle X X XFilament structure

X X X

Filament activation

X X

Flows X X X X X X

Intensity waves X X X X X

Nano-flares X X X XSeparatix heating

X X X X X

Loop thermal structure

X X X X X

Loop life cycle X X X

Magnetic carpet X X X

Bright point topology

X

Bright point thermal

structureX

Bright point life cycle

X

Coronal Hole Boundary

X

MHD waves X X X X

Solar Feature

Science Topic


First Second Third

QuietFlows/Longitudinal waves

MHD Waves Loop Life Cycle

EmergingJet Life Cycle Filament ActivationSeparatrix HeatingDelta SpotFlare Topology Loop Life Cycle Nano-Flares

Quiet SunCoronal HoleCoronal Hole BoundaryMagnetic carpet

Quiet SunMagnetic carpet Separatrix HeatingPolar Plume Jets

XBPXBP TopologyXBP Thermal Structure

XBP Life Cycle

FilamentFilament structure Filament activation

FlaresPreflareFlare Onset Flare Topology

Post flareCME Acceleration MHD Waves Current Sheet Inflows

Solar Feature Top Priorities for Different Solar FeaturesXRT

Active Region

All plans and observations will be conducted jointly with EIS & SOTSynoptic program is currently undefined


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18-April-2006XRT Team1 Initial Science Observations Solar-B XRT Ed DeLuca for the XRT Team.

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