Velocity structure of bright points in a coronal hole

1
Velocity structure of bright points in a coronal
hole

• Suguru Kamio, Hirohisa Hara,Tetsuya Watanabe
  (NAOJ),and Werner Curdt (MPS)

2
Introduction

• Jets are ejections fromcoronal bright points.
• Apparent velocity of EUVjets in coronal
  hole100 - 400 km/s
• They are important for understanding coronal
  heating and solar wind acceleration.

(Moses et al. 1997)
C IV
Ne VIII
(Wilhelm et al. 2002)
3
Jets and bright points

• Soft X-ray image showing Ioop-shaped bright
  points and associated jets in coronal hole.

EIS FOV
4
X-ray bright points in coronal hole

• EIS observation 16101824 UT
• One scan 256 x 256

5
Doppler shift

• Blueshift of 30 km/s above the bright point is
  interpreted as jets caused by reconnection.

Bright loop
(Shibata 1998)
(Kamio et al. 2007)
6
Hinode SUMER campaign

• Coronal hole in South pole
• HinodeEIS Coronal linesSOT SP full FOV
  mapXRT X-ray image
• SOHO/SUMEROIV, Ne VIII, and N IVTransition
  region and lower corona

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Transition region and corona
Hinode/EIS X-ray BP in coronal hole
SOHO/SUMER Supergranular Network
O IV 2x105K
Ne VIII 6x105K
Fe XII 2x106K
8
Roots of bright points
Contours O IV intensity

• O IV brightness outlines network structure.
• Roots of coronal bright points are co-spatial
  with O IV bright region.

9
Doppler map
Velocity Scale 30km/s Contours O IV intensity

• Transition region ubiquitous short jets (5)
  small scale structure of low lying field
• Corona several elongated jets (50)
  large scale structure in the higher corona
• No direct correlation due to observing time
  difference

10
Flux and bright points

• Stokes V signal with 0.3 resolution.
• Bright points are rooted in flux concentration.
• Only a small fraction of flux concentration is
  associated with bright points.

Contour Fe XII intensity
11
Summary

• Hinode-SUMER collaboration has allowed us to
  study different layers of solar atmosphere.
  ?Next campaign in Oct-Nov 2007
• Coronal bright points are rooted in flux
  concentrations of network structure.
• Coronal jet are elongated and isolated, while
  jets in the transition region are short and
  ubiquitous.
• It implies different connectivity of magnetic
  flux in the corona and transition region.

12
The Instrument

• Wavelength bands170Å-210Å250Å-290Å
• Slits slots1, 2, 40, and 266
• High resolutions0.0223Å/pixel 1/pixel
• High throughputMinimum number of
  reflectionMulti-layer coating of the
  mirror?Suitable for transient phenomena

13
Ne VIII

• Item

Contours O IV intensity
14
O IV

• Item