Meridional transport of magnetic flux in the solar wind between 1 and 10 AU: a theoretical analysis

Journal Article · Wed Jul 01 00:00:00 EDT 1987 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA092iA07p07241· OSTI ID:6148585

Pizzo, V J; Goldstein, B E

Pioneer 10 observations suggest that the mean (longitudinally averaged) solar wind azimuthal field strength, B/sub phi/, near the ecliptic plane falls off more rapidly with heliocentric distance than would be expected in a classic Parker expansion, showing a deficit of 10--20% (as compared to the projected 1-AU value) by 10 AU. Though this observational interpretation has been challenged by subsequent analyses of Voyager data, it has nevertheless stimulated efforts to explain the inferred deficit on the basis of systematic north-south magnetic pressure gradients generated by the differential spiral wrapping of magnetic field lines in interplanetary space. We reexamine this issue from the theoretical perspective using a three-dimensional MHD nonlinear numerical model for steady, corotating flow. For realistic solar wind parameters we find that a purely axisymmetric expansion is capable of producing sizable magnetic flux deficits only when there are substantial meridional gradients in mean flow conditions localized about the ecliptic plane near the sun. Even then the match between plausible flow states and significant mean B/sub phi/ deficit is achieved over such a limited parameter range that it is unlikely this mechanism alone can produce deficits of the magnitude inferred from the Pioneer data.

• Research Organization: High Altitude Observatory, National Center for Atmospheric Research, Boulder, Colorado
• OSTI ID: 6148585
• Journal Information: J. Geophys. Res.; (United States), Vol. 92:A7
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
INTERPLANETARY SPACE
SOLAR WIND
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETOHYDRODYNAMICS
PLASMA DRIFT
PRESSURE GRADIENTS
THREE-DIMENSIONAL CALCULATIONS
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC FIELDS
MECHANICS
SOLAR ACTIVITY
SPACE
640104* - Astrophysics & Cosmology- Solar Phenomena