The dynamic cusp

Journal Article · Sat Feb 29 23:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA02654· OSTI ID:5556876

Potemra, T A; Erlandson, R E; Zanetti, L J ^[1]; Arnoldy, R L ^[2]; Woch, J ^[3]; Friis-Christensen, E ^[4]

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1. John Hopkins Univ., Laurel, MD (United States)
2. Univ. of New Hampshire, Durham (United States)
3. Swedish Inst. for Space Physics, Kiruna (Sweden)
4. Danish Meteorological Inst., Copenhagen (Denmark)

A unique alignment of the Viking satellite with respect to a network of magnetometers in Greenland has provided the opportunity to study the relationship of pulsations and plasma characteristics in the dayside cusp. The presence of Pc 1 bursts, Pc 4-5 pulsations, and a tailward traveling twin vortex pattern of ionospheric convection suggests that the magnetosphere may have been temporarily compressed. Magnetic field data acquired at synchrotrons altitude from GOES 5 and on the ground from Huancayo support this suggestion. Plasma with ion dispersion characteristics associated with a cusp during southward IMF was detected by Viking over a 3.5{degree} range of latitude. The presence of standing Alfven waves and ring current ions suggest that this cusplike plasma was observed on closed geomagnetic field lines. As Viking moved further poleward, it detected a different region of plasma with characteristics associated with a cusp during northward IMF. The presence of plasma on closed field lines with southward IMF ion dispersion characteristics can be explained with a poleward moving plasma source. The authors suggest that the magnetosphere, during a northward IMF, is temporarily compressed by a solar wind pressure enhancement that produces the Pc 1 bursts, Pc 4-5 pulsations, and ionospheric vortices. As the magnetosphere recovers to its precompressed shape, the source of cusp plasma will move poleward until it reaches an equilibrium position for northward IMF. The Viking satellite, following in the wake of this source, will detect plasma with southward IMF characteristics until it reaches the latitude of the actual northward IMF cusp.

• OSTI ID: 5556876
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A3; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
GEOMAGNETIC FIELD
HYDROMAGNETIC WAVES
INTERPLANETARY MAGNETIC FIELDS
IONOSPHERE
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
MASS TRANSFER
MORPHOLOGY
PLANETARY IONOSPHERES
PLASMA DIAGNOSTICS
POLAR CUSP
SATELLITES
SOLAR ACTIVITY
SOLAR WIND
STANDING WAVES
VARIATIONS