Ground signatures of dayside magnetospheric boundary-layer phenomena

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5837749

McHenry, M A

Solar wind momentum at the Earth's magnetopause causes plasma to circulate inside the magnetosphere and in the ionosphere. Satellite observations have shown that two momentum exchange processes, magnetic reconnection and viscous interaction, are active. Associated with these, localized, sporadic changes in the electric currents and plasma velocity occur in the high latitude ionosphere; i.e. deep inside the terrestrial magnetosphere. In this study continuous, multiple point, ground based observations of the ionosphere are used to study features of the magnetopause related to reconnection and viscous interaction. Flux transfer events (FTEs) are one type of magnetic reconnection process observed at the magnetopause. Two FTE field-aligned current systems, which presumedly interact with the ionosphere, have been inferred and postulated. In this study an analysis is made of the expected ground magnetic field of these small-scale, field-aligned current systems interacting with the ionosphere. The effects of ground induction which occur when the current systems move relative to a ground observer is also examined. The author believes the lack of FTE signatures in ground observations may be due to the small area of the FTE ground signature or to a more complex FTE field aligned current system. Observations of ground magnetic field perturbations using a Greenland magnetometer chain show that traveling perturbations similar to the predicted FTE signatures exist in the high latitude ionosphere. The perturbations have a field-aligned current concentrated into filaments producing a radical ground magnetic field and an azimuthal, or vortex-like flow, plasma flow in the ionosphere.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 5837749
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOUNDARY LAYERS
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
FLUCTUATIONS
GROUND LEVEL
HELMHOLTZ INSTABILITY
INSTABILITY
INTERACTIONS
IONOSPHERE
LAYERS
LEVELS
MAGNETIC FLUX
MAGNETIC RECONNECTION
MAGNETOPAUSE
MOMENTUM TRANSFER
PLANETARY IONOSPHERES
PLASMA DRIFT
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA WAVES
SOLAR ACTIVITY
SOLAR WIND
VARIATIONS