CDAW 8 observations of plasmoid signatures in the geomagnetic tail: An assessment

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA11p15153· OSTI ID:7188508

Slavin, J A; Baker, D N; Fairfield, D H ^[1]; Craven, J D; Frank, L A ^[2]; Elphic, R C ^[3]; Galvin, A B; Richardson, I G ^[4]; Hughes, W J ^[5]; Manka, R H ^[6]; Mitchell, D G; Sibeck, D J ^[7]; Sanderson, T R ^[8]; Smith, E J ^[9]; Zwickl, R D ^[10]

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1. NASA Goddard Space Flight Center, Greenbelt, Maryland (USA)
2. Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa (USA)
3. Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California (USA)
4. Department of Physics and Astronomy, University of Maryland, College Park, Maryland (USA)
5. Department of Astronomy, Boston University, Boston, Massachusetts (USA)
6. National Research Council, Washington, D.C. (USA)
7. Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland (USA)
8. European Space Research and Technology Centre, Noordwijk, (Netherlands)
9. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California (USA)
10. NOAA Space Environment Laboratory, Boulder, Colorado (USA)

A primary objective of the Coordinated Data Analysis Workshop 8 (CDAW 8) was the critical assessment of the plasmoid hypothesis. In this study, various types of magnetic phenomena, including closed loops and flux ropes, were considered as candidates for producing the north-then-south magnetic field perturbations characteristic of the plasmoids observed in the magnetotail by ISEE 3 during the CDAW 8 A and G events. For these two events the principal axis analyses of the magnetic field data and supporting energetic particle and measurements are found to be consistent with the closed-loop model of plasmoids for which the plane of rotation for {bold B} lies near the GSE {ital X}--{ital Z} plane and only small field components lie in the minimum variance direction oriented largely along the {ital Y} direction. While small pitch angle spiraling of the field lines within these structures such as suggested by Hughes and Sibeck (1987) and Birn {ital et} {ital al}. (1989) cannot be definitively measured using single-spacecraft magnetometer observations, the ISEE 3 measurements are not consistent with moderate strength or Venus-type strong core field flux ropes. The event A and G plasmoids were preceded by smoothly draped lobe field lines and followed by strong southward fields in the postplasmoid plasma sheet as predicted by the reconnection model of substorms. This latter feature of the observations is consistent with plasmoids moving down the tail, at least in part, due to the Maxwell stress exerted by lobe field lines which were disconnected at the near-tail neutral line and have draped about the earthward side of the plasmoid. Calculations, based upon typical plasmoid and tail parameters, are presented which indicate that the {ital J}{times}{ital B} force associated with these disconnected lobe field lines may be sufficient to accelerate plasmoids up to the speeds observed by ISEE 3.

• OSTI ID: 7188508
• Journal Information: Journal of Geophysical Research; (USA), Vol. 94:A11; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
MAGNETOTAIL
PLASMOIDS
DATA ANALYSIS
DISTURBANCES
MAGNETIC FIELDS
MAGNETIC RECONNECTION
MAGNETIC STORMS
MAGNETOMETERS
PLASMA ACCELERATION
ACCELERATION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
MEASURING INSTRUMENTS
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena