The X-Ray Telescope aboard Solar-B: An OverviewTaro Sakao (ISAS/JAXA) and The XRT Team

XRT SciencesPhotosphere-Corona connectionFormation and heating of the corona incl. energy transport, storage, and dissipationOuter-corona investigation extending to CME and solar wind investigationsImaging observation of the soft X-ray/XUV corona with advanced imaging/temperature-diagnostic capabilitiesVast varieties of active, or even non-active, phenomena in the corona:

Investigation of Photosphere-Corona Connection with XRT

PhotosphericMagnetic Activity

Reservoir ?

Energy Storage Increase Spatial Scale

Transient Brightenings ?

Large-Scale Coronal Phenomena ?

Eruptive flaresCMEs...StorageReleaseImmediate ResponseTrigger ?Time scale: minutesSpatial scale: ~1 arcsecTime scale: daysSpatial scale: ~AR?Coronal BehaviorSOTXRT / EIS

Coronal Activity Assoc. with Evolution of an Active Region (from Morita & McIntosh 2005)

Typical Flare Evolution in the Growing Phase

Typical Flare Evolution in the Large-Flare-Productive Phase

(Morita and McIntosh 2005)

(Morita and McIntosh 2005)Investigate Temperature structure of the corona (both hot & cool loops) Pre-flare evolution leading to energy release Long-term evolution of coronal magnetic structure accompanying flare energy release, particularly for entire active regionstogether with photospheric magnetic evolution

XRT Advanced Features over Yohkoh SXTImaging/temerature-diagnositic capabilities for low-temperature (< 1MK) plasmas Observe entire SXR/XUV phenomena in the corona With back-thinned CCD together with optimum focal plane filters Highest-ever achieved angular resolution as GI imager, with wide FOV (covering the whole Sun) 1 arcsec pixel size Cadence as high as, or even better than, SXT High-cadence (1 s) observation with small FOV available Adjustable Focus Position Adds variety in observations: Highest angular-resolution (1 arcsec) for SOT/EIS FOV Full-sun observation with 23 arcsec

XRT Advanced Features over Yohkoh SXTImaging/temerature-diagnositic capabilities for low-temperature (< 1MK) plasmas Observe entire SXR/XUV phenomena in the corona With back-thinned CCD together with optimum focal plane filters Highest-ever achieved angular resolution as GI imager, with wide FOV (covering the whole Sun) 1 arcsec pixel size Cadence as high as, or even better than, SXT High-cadence (1 s) observation with small FOV available Adjustable Focus Position Adds variety in observations: Highest angular-resolution (1 arcsec) for SOT/EIS FOV Full-sun observation with 23 arcsec

XRT Advanced Features over Yohkoh SXTImaging/temerature-diagnositic capabilities for low-temperature (< 1MK) plasmas Observe entire SXR/XUV phenomena in the corona With back-thinned CCD together with optimum focal plane filters Highest-ever achieved angular resolution as GI imager, with wide FOV (covering the whole Sun) 1 arcsec pixel size Cadence as high as, or even better than, SXT High-cadence (1 s) observation with small FOV available Adjustable Focus Position Adds variety in observations: Highest angular-resolution (1 arcsec) for SOT/EIS FOV Full-sun observation with 23 arcsec

XRT Advanced Features over Yohkoh SXTImaging/temerature-diagnositic capabilities for low-temperature (< 1MK) plasmas Observe entire SXR/XUV phenomena in the corona With back-thinned CCD together with optimum focal plane filters Highest-ever achieved angular resolution as GI imager, with wide FOV (covering the whole Sun) 1 arcsec pixel size Cadence as high as, or even better than, SXT High-cadence (1 s) observation with small FOV available Adjustable Focus Position Adds variety in observations: Highest angular-resolution (1 arcsec) for SOT/EIS FOV Full-sun observation with 23 arcsec

Telescope performance to be presented by Ed Deluca-san et al. in the next talk

XRT Advanced Features over Yohkoh SXTImproved on-board observation control by the MDP/XRT system Automatic Exposure Control (AEC) Automatic Region Selection (ARS) Image-based Flare Detection (FLD; new feature) Table-based Observation Sequence Control e.g., Exposure tracking and stabilization for AEC Implementation of pre-flare data buffer memory inside MDP Potentially powerful tool for detailed observation of the pre-flare corona Investigation of pre-flare energy storage and release processes

LASCO/C2XRT FOV for Limb ObservationYohkoh SXT2.1 RSUN2.3 RSUNWide-FOV Observation of Outer Corona with Diagnostic Capability on Temperature Structure

LASCO/C2XRT FOV for Limb ObservationYohkoh SXTWide-FOV Observation of Outer Corona with Diagnostic Capability on Temperature StructureFrequent observation opportunity for the outer corona Temperature structure of the corona up to 2 Rsun (c.f. Foley et al. 1997 & Wheatland et al. 1997 with Yohkoh data) Tracking transient ejections (CMEs, filaments) in the corona2.1 RSUN2.3 RSUN

10010001000100101Cadence (sec)Flare CoreActive RegionGlobal Corona / Heliospheric(Hardware limit by Telescope)(w/o filter motion)(w/ adjacent filter motion)Non-flareFlareFull-SunYohkoh SXTFull-SunCoverage2 pxl size, or Q~75 (3 bit/pxl)XRTFOV vs CadenceObserving FOV Size (arcsec)(orbit-ave.)Cover SOT FOV

10010001000100101Observing FOV Size (arcsec)Cadence (sec)(Hardware limit by Telescope)(w/o filter motion)(w/ adjacent filter motion)Non-flareFlareFull-SunFull-SunCoverageXRTYohkoh SXTObservation with Pre-Flare BufferFlare CoreActive RegionFOV vs Cadence(orbit-ave.)~x 3Global Corona / HeliosphericCover SOT FOV2 pxl size, or Q~75 (3 bit/pxl)

10010001000100101Observing FOV Size (arcsec)Cadence (sec)(Hardware limit by Telescope)(w/o filter motion)(w/ adjacent filter motion)Non-flareFlareFull-SunFull-SunCoverageXRTYohkoh SXTFlare CoreActive RegionFOV vs Cadence(orbit-ave.)Global Corona / HeliosphericOuter corona investigationCover SOT FOV2 pxl size, or Q~75 (3 bit/pxl)Flare core with high spatial/temporal resolutionHigh-cadence observation on magnetic configuraitonand temperature evolution

Basic Features of the XRT

X-ray OpticsOpticsOptimized Wolter-I-like grazing incidence opticsFocal length2708 mmMirror micro-roughness6 expected (mirror characterization analysis in progress)Aperture size> 340 mmSpatial resolution68 % of encircled energy in 2 arcsec (at 0.523 keV)Wavelength range6 200 Effective area> 1.0 cm2 at 0.523 keVVisible Light OpticsFocal length2708 mmWavelength4305 (G-band)Focal Plane CCD CameraCCD deviceE2V (former Marconi)20482048 back-illuminated (13.5 mm pixel size)Field of view3434 arcmin (capable of covering the whole Sun)Image readout500 kpixel/s