HR: 0830h
AN: SH21B-0164    [PDF]
TI: The Relation Between the Solar Wind Velocity and the Magnetic Conditions of Coronal Holes
AU: * Hirano, M
EM: mhirano@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, 3-13 Honohara, Toyokawa, 442-8507 Japan
AU: Kojima, M
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, 3-13 Honohara, Toyokawa, 442-8507 Japan
AU: Tokumaru, M
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, 3-13 Honohara, Toyokawa, 442-8507 Japan
AU: Fujiki, K
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, 3-13 Honohara, Toyokawa, 442-8507 Japan
AU: Ohmi, T
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, 3-13 Honohara, Toyokawa, 442-8507 Japan
AU: Yamashita, M
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, 3-13 Honohara, Toyokawa, 442-8507 Japan
AU: Hakamada, K
AF: Department of Natural Science and Mathematics, Chubu University, 1200 Matsumoto-cho, Kasugai, 487-8501 Japan
AU: Hayashi, K
AF: W. W. Hansen Experimental Physics Laboratory, Stanford University, 455 Via Palou, Stanford, CA 94305-4085 United States
AB: It is thought that interplanetary space is filled by solar wind, which originates from coronal holes of various sizes and that the structure of each coronal hole is approximately uniform. Using this idea, we have performed a correlation study between solar wind velocity originating from coronal holes and photospheric/coronal magnetic fields from coronal holes. Interplanetary scintillation (IPS) observations allow us to estimate the global velocity structure in the solar wind for each Carrington rotation. We applied a tomographic analysis using IPS data to obtain 2-dimentional velocity distributions at 2.5 solar radii and then determined the average solar wind velocity, {\sl u}, originating from each coronal hole. Coronal holes are identified using FeI and HeI observation from the NSO/Kitt Peak and the average magnetic field strength, {\sl B}, of each coronal hole is calculated. Coronal magnetic fields above the coronal hole are computed using a potential-field source-surface model and the flux tube expansion rate, {\sl f}, is calculated for each coronal hole. We have calculated the correlation coefficient between {\sl u} and a combination of {\sl B} and {\sl f} (i.e. {\sl B}$^{m}$/{\sl f}\(^{n}\)) for 41 coronal holes. As a result, we have found that the value {\sl B}/{\sl f} shows a higher correlation with {\sl u} than the value {\sl B} (deduced by Fisk et. al. model, 1999) and the value {\sl f} (deduced by Wang and Sheeley model, 1991). We propose that the parameter, {\sl B}/{\sl f}, is an important indicator of the solar wind velocity originating from various kinds of coronal holes.
UR: http://stesun5.stelab.nagoya-u.ac.jp/index-e.html
DE: 2164 Solar wind plasma
DE: 2169 Sources of the solar wind
DE: 7509 Corona
DE: 7511 Coronal holes
DE: 7524 Magnetic fields
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting