Latitude and Solar-Cycle Dependence of Radial IMF Intensity
Abstract
I describe a simple procedure for extrapolating the observed solar magnetic field into the heliosphere, which averages the asymptotic fields computed using the standard “source surface” and “current sheet” models. The resultant field is characterized by strong latitudinal gradients (maintained by volume currents outside the source surface) and by abrupt reversals in direction at the current sheets. The model yields good agreement with the observed long-term variation of the radial IMF component in the ecliptic, and is used to predict the variation of |B r | along the latitudinal trajectory of Ulysses during 1990 1994. As found in earlier studies, the magnitude ofB r at any latitude is determined largely by the strength and relative orientation of the Sun's dipole moment.
- Publication:
-
Space Science Reviews
- Pub Date:
- April 1995
- DOI:
- 10.1007/BF00768778
- Bibcode:
- 1995SSRv...72..193W
- Keywords:
-
- heliosphere;
- latitude effects;
- magnetic fields;
- solar cycle;
- Ulysses