On the formation and evolution of plasmoids: A survey of ISEE 3 geotail data

Journal Article · Tue Dec 01 04:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JA01598· OSTI ID:6788794

Moldwin, M B; Hughes, W J ^[1]

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1. Boston Univ., MA (United States)

ISEE 3 magnetometer and electron plasma measurements from the 1983 Geotail Mission were surveyed to determine the magnetic and plasma properties of plasmoids and their evolution with distance downtail. Events were selected on the basis of a bipolar magnetic signature in either the geocentric solar magnetospheric B[sub z] and/or B[sub y] component; most had B[sub z] bipolar signatures. The authors found 366 events consistent with this signature while ISEE 3 was in the plasma sheet. Plasmoid length was determined using both the magnetometer and the electron plasma velocity data. They found the average length of plasmoids is 16.7 [plus minus] 13.0 R[sub E], significantly smaller than previous estimates. Many plasmoids have a well-defined magnetic core field, characterized by a field strength maximum at the center of the pass through the structure. The size, velocity, magnetic core strength, and B[sub z] field amplitude of plasmoids do not depend on distance beyond 100 R[sub E] downtail. The average electron temperature inside plasmoids drops by a factor of 2 and the electron density increases by a factor of 2 as plasmoids propagate from near Earth distances (within 100 R[sub E] of the Earth) to the deep tail. They conclude that the stable size of the plasmoids, the density increase and the temperature decrease are consistent with a flux of cold electrons into the plasmoid. The strong correlation of interplanetary magnetic field B[sub y] an hour before the event with the strength and direction of B[sub y] observed inside plasmoids, the existence of events with the bipolar signature in both the B[sub y] and B[sub z] components, and the possible mass flux all are consistent with plasmoids being open' magnetic structures.

• OSTI ID: 6788794
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A12; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRON DENSITY
ELECTRON TEMPERATURE
GEOMAGNETIC FIELD
MAGNETIC FIELDS
MAGNETIC PROPERTIES
MAGNETOTAIL
PHYSICAL PROPERTIES
PLASMA
PLASMA DRIFT
PLASMA SHEET
PLASMOIDS
SYNTHESIS