The formation, structure, and evolution of plasmoids
The configuration and topology of the Earth's magnetotail is radically altered during geomagnetic substorms by the formation and subsequent ejection of large scale magnetic and plasma structures called plasmoids. The formation, structure, evolution and topology of plasmoids are studied by examining the magnetic and plasma data from the 1983 ISEE 3 Geotail Mission. This deep tail data set is combined with observations in the middle tail by IMP 8, at geosynchronous orbit and from ground auroral magnetometer stations to develop a unified flux rope plasmoid model. It is found that plasmoids are highly correlated with geomagnetic substorms, are large (approximately 10-20 R(sub E)), rapidly tailward moving (approximately 500 km s(exp -1)) magnetic flux rope structures, and are very stable (i.e., do not change size, downtail velocity, internal electron plasma energy density, or magnetic field signatures as a function of distance downtail). Evidence for the flux rope topology includes the strong correlation of the direction of the core magnetic field in the interplanetary magnetic field direction, the existence of plasmoids with various orientations with respect to the GSM xy plane, and the apparent mass flux of cool magnetosheath electrons into the structure as the plasmoid propagates downtail. Plasmoids are found to be a ubiquitous feature of the distant magnetotail and are occasionally observed in the relatively near-Earth tail by IMP 8. Due to the apparent large vertical extent of plasmoids, they affect the shape and size of the entire magnetosphere as they propagate downtail. Indirect observations of plasmoids are made in the plasma sheet boundary layer, the lobe, and the magnetosheath adjacent to the magnetopause. Because of their prevalence, size, velocity and magnetic and plasma energy content, plasmoids play an important role in the configuration, morphology, topology, and energy budget of the magnetosphere during geomagnetic substorms.
- Research Organization:
- Boston Univ., MA (United States)
- OSTI ID:
- 6442993
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ENERGY DENSITY
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETIC STORMS
MAGNETOPAUSE
MAGNETOSHEATH
MAGNETOTAIL
MOTION
PLASMA SHEET
PLASMOIDS
SYNTHESIS