Distribution of convection potential around the polar cap boundary as a function of the interplanetary magnetic field

Journal Article · Sun Oct 01 04:00:00 EDT 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA10p13447· OSTI ID:5831694

Lu, G; Reiff, P H; Karty, J L ^[1]; Hairston, M R; Heelis, R A ^[2]

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1. Rice Univ., Houston, TX (USA)
2. Univ. of Texas, Richardson (USA)

Plasma flow data from the AE-C, AE-D and DE 2 satellites have been used to systematically study the distribution of the convection potential around the polar cap boundary under a variety of different interplanetary magnetic field (IMF) conditions. For either a garden hose (B{sub x}B{sub y}<0) or ortho-garden hose (B{sub x}B{sub y}>0) orientation of the IMF, the potential distribution is mainly affected by the sign of B{sub y}. In the northern hemisphere, the zero potential line (which separates the dusk convection cell from the dawn cell) on the dayside shifts duskward as B{sub y} changes from positive to negative. But in the southern hemisphere, a dawnward shift has been found, although the uncertainties are large. The typical range of displacement is about {plus minus}1.5 hours MLT. Note that this shift is in the opposite direction from most simple schematic models of ionospheric flow; this reflects the fact that the polar cap boundary is typically more poleward than the flow reversal associated with the region 1 current system, which shifts in the opposite direction. Thus the enhanced flow region typically crosses noon. In most cases a sine wave is an adequate representation of the distribution of potential around the boundary. However, in a few cases the data favors (at the 80% confidence level) a steeper gradient near noon, more indicative of a throat. The potential drop at the duskside boundary is almost greater than at the dawnside boundary. A slight duskward shift of the patterns observed as the IMF changes from garden hose to ortho-garden hose conditions. Analytic equipotential contours, given the potential function as a boundary condition, are constructed for several IMF conditions.

• OSTI ID: 5831694
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A10; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOUNDARY CONDITIONS
BOUNDARY LAYERS
DYNAMICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
EARTH PLANET
ELECTRIC POTENTIAL
INTERACTIONS
INTERPLANETARY MAGNETIC FIELDS
IONOSPHERE
LAYERS
MAGNETIC FIELDS
MECHANICS
NORTHERN HEMISPHERE
ORIENTATION
PLANETARY IONOSPHERES
PLANETS
PLASMA DRIFT
POLAR REGIONS
SATELLITES
SOLAR ACTIVITY
SOLAR WIND
SOUTHERN HEMISPHERE