Slow Solar Wind: Sources and Components of the Stream Structure at the Solar Maximum
Abstract
We study the sources and components of the solar-wind spatial stream structure at the maximum of the solar cycle 23. In our analysis, we use several independent sets of experimental data: radio-astronomical observations of scattered radiation from compact sources with the determination of the distance from the Sun to the inner boundary of the transonic-flow transition region (R_in); calculated data on the magnetic-field intensity and structure in the solar corona, in the solar-wind source region, obtained from optical measurements of the photospheric magnetic-field intensity at the Stanford Solar Observatory (USA); and observations of the white-light corona with the LASCO coronograph onboard the SOHO spacecraft. We show that at the solar maximum, low-speed streams with a transition region located far from the Sun dominate in the solar-wind structure. A correlation analysis of the location of the inner boundary R_in and the source-surface magnetic-field intensity |B_R| on a sphere R = 2.5 R_solar is revealed the previously unknown lowest-speed streams, which do not fit into the regular relationship between the parameters R_in and |B_R|. In the white-light corona, the sources of these streams are located near the dark strip, a coronal region with a greatly reduced density; the nonstandard parameters of the streams probably result from the interaction of several discrete sources of different types.
- Publication:
-
Astronomy Letters
- Pub Date:
- September 2003
- DOI:
- 10.1134/1.1607501
- Bibcode:
- 2003AstL...29..629V