Papers on Solar and Heliospheric Physics
Heliospheric tomography using interplanetary scintillation observations: 2. Latitude and heliocentric distance dependence of solar wind structure at 0.1–1 AU
Article first published online: 20 SEP 2012
Copyright 1998 by the American Geophysical Union.
Journal of Geophysical Research: Space Physics (1978–2012)
Volume 103, Issue A2, pages 1981–1989, 1 February 1998
How to Cite
1998), Heliospheric tomography using interplanetary scintillation observations: 2. Latitude and heliocentric distance dependence of solar wind structure at 0.1–1 AU, J. Geophys. Res., 103(A2), 1981–1989, doi:10.1029/97JA02162., , , , , , and (
- Issue published online: 20 SEP 2012
- Article first published online: 20 SEP 2012
- Manuscript Accepted: 23 JUL 1997
- Manuscript Received: 12 FEB 1997
Interplanetary scintillation is a useful means to measure the solar wind in regions inaccessible to in situ observation. However, interplanetary scintillation measurements involve a line-of-sight integration, which relates contributions from all locations along the line of sight to the actual observation. We have developed a computer assisted tomography (CAT) program to reduce the adverse effects of the line-of-sight integration. The program uses solar rotation and solar wind motion to provide three-dimensional perspective views of each point in space accessible to the interplanetary scintillation observations and optimizes a three-dimensional solar wind speed distribution to fit the observations. We analyzed IPS speeds observed at the Solar-Terrestrial Environment Laboratory and confirmed that (1) the solar wind during the solar minimum phase has a dominant polar high-speed solar wind region with speeds of about 800 km s−1 and within 30° of the solar equator speeds decrease to 400 km s−1 as observed by Ulysses, and (2) high-speed winds get their final speed of 750–900 km s−1 within 0.1 AU, and consequently, that acceleration of the solar wind is small above 0.1 AU.