Understanding the Solar Sources of In Situ Observations
Abstract
The solar wind can, to a good approximation be described as a two-component flow with fast, tenuous, quiescent flow emanating from coronal holes, and slow, dense and variable flow associated with the boundary between open and closed magnetic fields. In spite of its simplicity, this picture naturally produces a range of complex heliospheric phenomena, including the presence, location, and orientation of corotating interaction regions and their associated shocks. In this study, we apply a two-step mapping technique, incorporating a magnetohydrodynamic model of the solar corona, to bring in situ observations from Ulysses, WIND, and ACE back to the solar surface in an effort to determine some intrinsic properties of the quasi-steady solar wind. In particular, we find that a ``layer'' of ~35,000 km exists between the Coronal Hole Boundary (CHB) and the fast solar wind, where the wind is slow and variable. We also derive a velocity gradient within large polar coronal holes (that were present during Ulysses' rapid latitude scan) as a function of distance from the CHB. We find that v = 713 km/s + 3.2 d, where d is the angular distance from the CHB boundary in degrees.
- Publication:
-
Solar Wind Ten
- Pub Date:
- September 2003
- DOI:
- 10.1063/1.1618546
- Bibcode:
- 2003AIPC..679...79R
- Keywords:
-
- 96.60.Vg;
- 96.60.Pb;
- 96.50.Ci;
- Particle emission solar wind;
- Solar wind plasma;
- sources of solar wind