Ionospheric convection signatures and magnetic-field topology

Technical Report · Sun Nov 01 04:00:00 EST 1987

OSTI ID:7149673

Coley, W R; Heelis, R A; Hanson, W B; Reiff, P H; Sharber, J R

A statistical study is presented of signatures of the high-latitude ionospheric convection pattern and the simultaneously observed energetic electron precipitation. Most often convection cells are found in which the sunward flowing-region contains auroral particle precipitation but the antisunward flowing region does not. However, observations also show the frequent occurrence of convection cells in which neither the antisunward nor the sunward flowing plasma region contains auroral particle precipitation. These findings may appear within the dawnside or duskside convection pattern and strongly suggest that such convection cells may be associated with open magnetic-field lines that thread the magnetotail lobes. Examination of the interplanetary magnetic field (IMF) data shows that this lobe cell convection signature is most likely to be accompanied by the signature of dayside merging when the IMF has a significant y component but is directed southward. A lobe convection cell has a location and sense of circulation that are dependent on the sign of By. For the northern hemisphere, clockwise circulation displaced to the duskside appears roughly 35% of the time when By is positive, and anticlockwise circulation displaced to the dawnside appears when By is negative. The same circulation sense and location exist in the southern hemisphere for the opposite polarity of By. At times of northward IMF, the circulation within the polar cap can be at least partially on closed field lines and cannot be easily reconciled with merely a distortion of the standard two-cell convection pattern. The significance of these results to several models of the solar wind/magnetosphere interaction is discussed.

• Research Organization: Southwest Research Inst., San Antonio, TX (USA)
• OSTI ID: 7149673
• Report Number(s): AD-A-191201/3/XAB
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
CHARGED-PARTICLE PRECIPITATION
CONVECTION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
EARTH PLANET
ELECTRON PRECIPITATION
ELECTRONS
ELEMENTARY PARTICLES
ENERGY TRANSFER
FERMIONS
HEAT TRANSFER
INTERACTIONS
INTERPLANETARY SPACE
IONOSPHERE
LEPTONS
MAGNETIC FIELDS
MASS TRANSFER
MATHEMATICS
NORTHERN HEMISPHERE
PARTICLES
PLANETARY IONOSPHERES
PLANETS
SOLAR ACTIVITY
SOLAR WIND
SOUTHERN HEMISPHERE
SPACE
STATISTICS
TOPOLOGY