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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0076

Observation of an equatorial coronal hole

plan term


@ @


 name : Hayashi @  e-mail : keiji[at]sun.stanford.edu

contact person in HINODE team

 name : Kano & Sekii @  e-mail : ryouhei.kano[at]nao.ac.jp

 abstract of observational proposal
High-speed solar wind with velocity of about 700 km/s was detected by ACE from July 12 to 16, 2008. Just before, on July 10-12, an equatorial coronal hole had passed the central meridian. Various models (e.g. the Wang-Sheeley-Arge solar wind speed prediction model with potential field approximation and our MHD model) strongly suggest that the high-speed solar wind originated from this equatorial coronal hole.

Because the global structure of the solar corona is simple and dipole-dominated during solar minimum, the sources of the solar wind is well determined.

Most high speed streams originates in the polar regions that are difficult to observe. Because magnetic field in an equatorial coronal hole near the central
meridian is almost aligned with the line-of-sight direction, this is a good opportunity to precisely measure the vector magnetic field and plasma properties
in the source of high-speed solar wind. We would like to compare the Hinode observations to the solar-wind observations with near-Earth space probes (like ACE) or with IPS (interplanetary scintillation of radio waves).

We are interested in the following two topics for solar wind.

1) To determine physical parameters (B, T, Ne and so on) in the coronal hole as a source of energy and momentum into the solar wind.

2) To find any quantitative relation between coronal-hole parameters and solar-wind parameters by the comparison between Hinode and solar-wind observations. It may be a very new finding to identify sources of the measured solar wind.

 request to SOT
SOT-FG: 160Mbits by Q75
  Stokes-IV: FOV 164"x164", summing 2x2, cadence 5min
  CaII-H and G-band 111"x111", summing 2x2, cadence 5min

SOT-SP: 310Mbits by Q75
  Stokes-IQUV: FOV 164"x164", 0.32"/pixel

 request to XRT
XRT: 70Mbits by Q75
  a pair of Al/mesh and Ti/poly (or Al/poly and Ti/poly etc.)
  FOV 256"x256" at least (512"x512" desired),
  summing 1x1, cadence 2min for 1pair.
  At least, a pair of images with full frame with 2x2 summing.

 request to EIS
EIS: Study ID 241 PRY_footpoints_lite
TITLE Low data rate study for coronal loop footpoints
TARGET Active Region

Raster #1
Parameter Value
ACRONYM Cool_lines_lite
LL_ID 110
SCAN STEP SIZE (arcsec) 2
WINDOW WIDTHS (pixels) 56,48,48,40,32,56,32,32,32,56,32,32,32,32,32,32,32,32
WINDOW HEIGHT (pixels) 240

Line List #1
Line Wavelength (Angstroms)
FeX 184.33
FeXII 186.75
FeXI 188.35
FeXXIV 192.01
CaXVII 192.82
FeXII 195.00
FeXIII 202.04
FeXIII 203.83
OV 248.46
HeII 256.40
FeXVI 262.98
MgVI 268.99
FeXIV 274.20
SiVII 275.35
MgV 276.58
MgVII 278.39
MgVII 280.75
FeXV 284.16

 other participating instruments

Target: We would like to observe an equatorial coronal hole passing the central meridian. The first candidate is the coronal hole which was observed around July 11. It was located around 300 degrees in the Carrington longitude with the size of 10-20 degrees in heliographic coordinates. It will pass the central meridian again on August 7 and September 3. It will take about 24 hours to cross. If the coronal hole above disappears before the next meridian passage, we would like to observe another equatorial coronal hole which is well developed like the above.

Priority of observables: We would like to observe the following set at three latitudinal positions (e.g. -160", 0" and +160") in a coronal hole, to increase the possibility that the Hinode observes the source of solar wind which will be detected near the Earth.

- The longitudinal magnetic component and the coronal temperature structures has the highest priority among these observables.

- The cadence can be adjusted lower, because phenomena we are interested in are essentially shower.

- We would like to keep observations at some latitudinal positions, to increase the possibility that the Hinode observes sources of solar winds which will be detected near the Earth (with ACE, for example).

Data rate: ~ 700Mbits for one position, and about 2000Mbits in total (for 3 positions).

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