New Views of the Solar Corona with Hinode X-Ray Telescope (XRT)

Taro Sakao (ISAS/JAXA)

and the XRT Team

(ISAS/JAXA, SAO, NAOJ, NASA/MSFC)

XRT Sciences

• Photosphere-Corona connection• Formation and heating of the corona

incl. energy transport, storage, and dissipation• Outer-corona investigation

extending to CME and solar wind investigations

Imaging observation of the soft X-ray/XUV corona with advanced imaging/temperature-diagnostic capabilities

Vast varieties of active, or even non-active, phenomena in the corona:

Hinode XRT

Front Door and Hinge Assembly

Electrical Box

Ascent Vents2 places

Graphite Tube Assembly

CCD Cameraand Radiator

Grazing IncidenceX-ray Mirror

Back-Illuminated CCD

Optimized set of focal-plane filters

Sophisticated observation control by MDP

Al/Mesh

Al/Poly

C/P

oly

Ti/P

oly

Thin

-Be

Med

-Be Med-Al

Thick-Al

Thick-Be

Optimized filter selection and layout Adjacent filter pairs for temperature diagnostics Both SXT-like and TRACE-like filters included in the set

Low temperature ( 1 MK) diagnostics≦

High-temperature plasmas

Temperature Diagnostics with XRT

Scientific Location of Hinode XRT(Angular resolution and temperature range)

Angular resolution(CCD Pixel Size)

Tem

per

atu

re r

ange

0.5”1”2.5”

Yohkoh/SXT(Full Sun)

SoHO/EIT(Full Sun)

TRACE (Partial)

Hinode/XRT(Full Sun)

～ 2 MK

100 1000

1000

100

10

1

Observing FOV Size (arcsec)

Cad

ence

(se

c)

(Hardware limit by Telescope)

(w/o filter motion)

(w/ adjacent filter motion)

Non-flare

Flare

Full-Sun

Full-SunCoverage

XRT

Yohkoh SXT

Flare CoreActive Region

FOV vs Cadence

(orbit-ave.)

Global Corona / Heliospheric

Outer corona investigation

Cover SOT FOV

2” pxl size, or Q~75 (3 bit/pxl)

Flare core with high spatial/temporal resolution

High-cadence observation on magnetic configuraitonand temperature evolution

An-order-of-magnitude increased exposure cadence particularly for non-flare observations

28 October 2006Hinode XRT

■ Superior images with high spatial resolution and with high contrast■ High cadence exposures■ Imaging capability for low temperature (~1 MK) plasmas

…ROI covering SOT/EIS FOV plus Synoptic full-Sun FOV (4 times a day) 　 1,000–2,000 exposures per day

Started observation from Oct. 23 last year

＊ Numerous XBPs now showing loop structures

＊ X-ray jet activities in polar regions

＊ Activities in ‘quiet’ regions and coronal holes

＊ Structure in diffuse corona

＊ Transient brightenings (microflares) in ARs

＊ Loop structure for flares

Hinode X-Ray Telescope (XRT)

Hinode XRT and Yohkoh SXT Imagesat a Same Solar Activity Phase

Hinode XRT Yohkoh SXT

Hinode XRT Yohkoh SXT

Active Region Imaging

Hinode XRT Yohkoh SXT

Quiet Regions

Hinode XRT Yohkoh SXT

X-ray Bright Points

Bright points now resolved into ensemble of loops.

2

2

13

1

3

2

1 3

2

1 3

2007/04/16–17 Al/Mesh 8 s Exposures; 20 min Cadence

X-ray Jets in Polar Regions

~10 events/hr　… 40,000 times higher detection rate than Yohkoh SXT- Relationship with polar photospheric mag. field?- Implication to high speed solar wind?　　 (Apparent jet velocity ~200 km/s)

(Cirtain et al. 2007, Savcheva et al. 2007, Shimojo et al. 2007)

(Al/Poly Filter)

Activity in Quiet Sun and Coronal Holes

(Ti/Poly Filter)

Transient Brightenings (Microflares)

Continuous Upflow of Plasmas

- Apparent upflow velocity ~140 km/s along (apparently open) field lines. [Subsonic]

- Temperature ~1.3 MK Density ~2 x 109 /cm3

-Mass loss rate ~2 x 1011 g/s [Good fraction of mass loss rate by solar wind]

(Ti/Poly Filter)(Sakao et al. 2007)

Cusp Structure for LDE Loops

Dec

. 1

7 1

2:00

Dec

. 1

8 0

0:00

Dec

. 1

8 1

2:00

C

B

M

(Al/Poly Filter)

Loop Structure for an Impulsive Flare

Dec

. 1

3 0

0:00

12:0

0

06:0

0

(Thin-Be Filter)

C

X

M

Temperature Distribution/Evolution Across the Whole Sun

(Narukage et al. 2007)

Height Dependence of Coronal Temperatures around a Polar Coronal Hole

2007 Feb.17

温度

Coronal Hole Temperature: 1.0–1.5 MK

Corona Hole Density: 　　 0.5 ～ 1.0 　ｘ 108 cm-3

密度

(Kano et al. 2007)

Remove Mirror ScatteringEffect by Utilizing Eclipse Data

密度

gradient(?)

0.9x106〜 1.5x106

erg sec-1 cm-2.

加熱源

0.1 Rs 0.2 Rs

Summary (1)• XRT holds a unique position among solar SXR/E

UV telescopes currently on orbit or being planned:* Continuous coverage of the entire temperature range in the corona for 1 MK plasmas≳ … Capable of observing entire plasma processes that take place in the corona, with temperature diagnostic capability* High angular resolution/contrast observations for high temperature ( 2 MK) plasmas≳

• High cadence observations… dynamics in quiet Sun/coronal hole regions

Summary (2)• Structure and evolution of coronal magnetic field

s and their associated temperatures

• Expected to serve as a key tool for investigating photosphere-corona connection. At the same time, may have non-negligible impact on heliospheric study.

Thank You