MHD simulation of B/sub y/-dependent magnetospheric convection and field-aligned currents during northward IMF

Journal Article · Sun Nov 01 04:00:00 EDT 1942 · J. Geophys. Res.; (United States)

OSTI ID:5009628

Ogino, T; Walker, R J; Ashour-Abdalla, M; Dawson, J M

We have used a high-resolution and time-dependent three-dimensional magnetohydrodynamic (MHD) model to study the interaction between the solar wind and the earth's magnetosphere during intervals when the interplanetary magnetic field (IMF) has both a B/sub y/ component and northward B/sub z/ component. When the IMF is northward, the palsma sheet thickens near the noon-midnight meridian and extends projections into the northern and southern lobes. When projected onto the polar cap, this appears as a narrow channel extending from midnight toward noon. This plasma sheet extension from the nightside toward the dayside shifts toward dawn for B/sub y/<0 and toward dusk for B/sub y/<0 and toward dusk for B/sub y/>0. Two types of upward field-aligned currents were found: an arc-shaped current which extends around the auroal zone and a tail lobe region 1 current running almost parallel to the sun-earth line. Like the plasma sheet extension the sun-aligned tail lobe region 1 current moves across the northern polar cap from dusk to dawn when the IMF orientation chagnes from duskward to dawnward during northward IMF. At latitudes north of the region 1 current in the polar cap the currents have the same direction as the region 2 currents (i.e., upward at dawn and downward at dusk). As the IMF orientation changes from northward to dawnward, the currents rotate such that the upward current joins wit the upward region 1 current, while the earthward current expands in the polar region. These magnetospheric features can be well explained by high-latitude merging cells and tail lobe convection cells resulting from antiparallel merging between the northward IMF and the tail field.

• Research Organization: Institute of Geophysics and Planetary Physics, University of California, Los Angeles
• OSTI ID: 5009628
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 90:A11; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPUTERIZED SIMULATION
CONVECTION
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
ENERGY TRANSFER
FLUID MECHANICS
HEAT TRANSFER
HYDRODYNAMICS
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MASS TRANSFER
MATHEMATICAL MODELS
MECHANICS
SIMULATION
SOLAR ACTIVITY
SOLAR WIND
THREE-DIMENSIONAL CALCULATIONS