Ionospheric disturbance dynamo

Journal Article · Tue Apr 01 00:00:00 EST 1980 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA085iA04p01669· OSTI ID:5460515

Blanc, M; Richmond, A D

A numerical simulation study of the thermospheric winds produced by auroral heating during magnetic storms, and of their global dynamo effects, establishes the main features of the ionospheric disturbanc dynamo. Driven by auroral heating, a Hadley cell is created with equatorward winds blowing above about 120 km at mid-latitudes. The transport of angular momentum by these winds produces a subrotation of the midlatitude thermosphere, or westward motion with respect to the earth. The westward winds in turn drive equatorward Pedersen currents which accumulate charge toward the equator, resulting in the generation of a poleward electric field, a westward E x B drift, and an eastward current. When realistic local time conductivity variations are simulated, the eastward mid-latitude current is found to close partly via lower latitudes, resulting in an 'anti-Sq' type of current vortex. Both electric field and current at low latitudes thus vary in opposition to their normal quiet-day behavior. This total pattern of distrubance winds, electric fields, and currents is superimposed upon the background quiet-day pattern. When the neutral winds are artificially confined on the nightside, the basic pattern of predominantly westward E x B plasma drifts still prevails on the nightside but no longer extends into the dayside. Considerable observational evidence exists, suggesting that the ionospheric disturbance dynamo has an appreciable influence on storm-time ionospheric electric fields at middle and low latitudes.

• Research Organization: Centre National d'Etudes de Telecommunications, Centre de Recherche en Physique de l'Environnement 92131 Issy-les-Moulineaux, France
• OSTI ID: 5460515
• Journal Information: J. Geophys. Res.; (United States), Vol. 85:A4
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
TRAVELLING IONOSPHERIC DISTURBANCE
ELECTRIC FIELDS
ANGULAR MOMENTUM
IONOSPHERE
MAGNETIC BAYS
MAGNETIC STORMS
PLASMA
SOLAR WIND
THERMOSPHERE
DISTURBANCES
EARTH ATMOSPHERE
IONOSPHERIC STORMS
PLANETARY IONOSPHERES
SOLAR ACTIVITY
640203* - Atmospheric Physics- Magnetospheric Phenomena- (-1987)