Ionospheric convection driven by NBZ currents

Journal Article · Fri May 01 04:00:00 EDT 1987 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA092iA05p04491· OSTI ID:6214920

Rasmussen, C E; Schunk, R W

Computer simulations of Birkeland currents and electric fields in the polar ionosphere during periods of northward interplanetary magnetic field (IMF) were conducted. When the IMF z component is northward, an additional current system, called the NBZ current system, is present in the polar cap. These simulations show the effect of the addition of NBZ currents on ionospheric convection, particularly in the polar cap. When the total current in the NBZ system is roughly 25% to 50% of the net region 1 and 2 currents, convection in the central portion of the polar cap reverses direction and turns sunward. This creates a pattern of four-cell convection with two small cells located in the polar cap, rotating in an opposite direction from the larger cells. The effects of varying ionospheric conductivity were studied by considering both a constant voltage source and a constant current source. Conductivity gradients due to seasonal and local time variations in solar production were considered, as well as gradients due to electron precipitation. When the Birkeland currents are fixed (constant current source), the electric field is reduced in regions of relatively high conductivity, which affects the pattern of ionospheric convection. Day-night asymmetries in conductivity change convection in such a way that the two polar-cap cells are located within the large dusk cell. When ionospheric convection is fixed (constant voltage source), Birkeland currents are increased in regions of relatively high conductivity. Ionospheric currents, which flow horizontally to close the Birkeland currents, are changed appreciably by the NBZ current system. The principal effect is an increase in ionospheric current in the polar cap. Copyright American Geophysical Union 1987.

• Research Organization: Center for Atmospheric and Space Sciences, Utah State University, Logan
• OSTI ID: 6214920
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 92:A5; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHARGED-PARTICLE PRECIPITATION
COMPUTERIZED SIMULATION
CONVECTION
CURRENTS
EARTH ATMOSPHERE
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRICAL PROPERTIES
ELECTRON PRECIPITATION
ENERGY TRANSFER
HEAT TRANSFER
INTERPLANETARY MAGNETIC FIELDS
IONIC CONDUCTIVITY
IONOSPHERE
MAGNETIC FIELDS
MASS TRANSFER
PHYSICAL PROPERTIES
PLANETARY IONOSPHERES
POLAR REGIONS
SIMULATION
VARIATIONS