Magnetospheric convection and upper atmospheric dynamics

Journal Article · Wed Dec 01 04:00:00 EST 1976 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA081i034p05822· OSTI ID:7236586

Straus, J M; Schulz, M

Ionospheric plasma, driven into motion by the magnetospheric convection electric field, interacts with the neutral upper atmosphere via collisions. These collisions provide both a momentum source (ion drag) and an energy source (Joule heating) for the neutral atmosphere. A three-dimensional numerical model has been used to investigate the dynamical effects of this interaction on the neutral upper atmosphere. The effects of Joule heating of the redistribution of heat input by global horizontal winds, and of adiabatic heating and cooling associated with vertical motions, all depend on the neutral wind velocity. Thus the coupled set of neutral hydrodynamic and ion mobility equations is solved self-consistently in order to determine the global neutral density, temperature, and wind fields simultaneously. The Joule heating rate, although small at low latitudes, increases strongly with latitude ..lambda.. up to ..lambda..approx.70degree and becomes comparable to that due to euv absorption there. Joule heating also provides a heat source at night, whereas euv heating provides none. Thermospheric temperatures and densities rise in response to the additional heating caused by ion--neutral collisions. The thermospheric wind fields are affected in two ways by magnetospheric convection. Joule heating causes a general equatorward flow which opposes the daytime poleward and the nighttime equatorward flow caused by euv heating. Ion drag, on the other hand, causes an increase in the neutral poleward motion during the day and an equatorward motion at night. Thus the combined effects of ion drag and Joule heating lead to a substantial increase in the nighttime neutral meridional velocity; the effect during the day depends on the relative size of the effects of ion drag and Joule heating. These results emphasize the importance of the interaction among the magnetosphere and the neutral upper atmosphere. (AIP)

• Research Organization: Space Sciences Laboratory, Aerospace Corporation, El Segundo, California 90245
• OSTI ID: 7236586
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 81:34; 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
CONVECTION
EARTH ATMOSPHERE
ENERGY TRANSFER
HEAT TRANSFER
HEATING
ION DRIFT
IONOSPHERE
JOULE HEATING
MAGNETOSPHERE
PLASMA HEATING
THERMOSPHERE
WIND