Interplanetary control of high-latitude electrodynamics

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6856039

Burke, W J; Doyle, M A

This paper reviews recent observational development concerning the influence of the solar wind (SW) and the interplanetary magnetic (IMF) field on magnetospheric processes. Subsequent to sudden compressions of the magnetosphere observed by the Dynamic Explorer satellite, the entire auroral oval is bombarded by previously trapped particles. Whether this is followed by a main phase storm or a theta aurora depends on the north-south polarity of the IMF. The potential drop across the polar cap is shown to correlate with the interplanetary electric field. However the potential across the polar cap is much less than the potential across the magnetosphere in the solar wind. During periods of northward IMF, regions of sunward convection, with an attendant field aligned current system, are found in the sunlit ionosphere on the day of the magnetic dawn-dusk meridan. On the night side of this meridian and in the darkened polar cap, electric fields and field-aligned currents show filamentary structures. Electron precipitation in the polar cap varies from nearly uniform polar rain during periods of southward IMF to structured polar rain and sun-aligned arcs when the IMF has a northward component. The theta aurora detected by the imaging system on Dynamics Explorer appears in regions of sunward convection accompanied by downcoming O/sup +/ ions. This suggests that the lobes of the magnetotail are bifurcated by closed, plasma-sheet field lines. At lower magnetic latitudes the systematics of the equatorward boundary of auroral electron precipitation are indirectly controlled by the interplanetary electric field.

• Research Organization: Air Force Geophysics Lab., Hanscom AFB, MA (USA)
• OSTI ID: 6856039
• Report Number(s): AD-A-176326/7/XAB
• Country of Publication: United States
• Language: English

Related Subjects

640104 -- Astrophysics & Cosmology-- Solar Phenomena
640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALIGNMENT
ATMOSPHERIC PRECIPITATIONS
AURORAE
AURORAL OVAL
CHARGED PARTICLES
CHARGED-PARTICLE PRECIPITATION
CONVECTION
CURRENTS
DYNAMICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC FIELDS
ELECTRODYNAMICS
ELECTRON PRECIPITATION
ELECTRONS
ELEMENTARY PARTICLES
ENERGY TRANSFER
FERMIONS
FILAMENTS
HEAT TRANSFER
IMAGES
INTERPLANETARY MAGNETIC FIELDS
INTERPLANETARY SPACE
IONS
LEPTONS
MAGNETIC FIELDS
MAGNETIC STORMS
MASS TRANSFER
MECHANICS
POLAR REGIONS
PRECIPITATION
RAIN
SEPARATION PROCESSES
SOLAR ACTIVITY
SOLAR WIND
SPACE