Magnetospheric boundary dynamics: DE 1 and DE 2 observations near the magnetopause and cusp

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA02167· OSTI ID:5310789

Maynard, N C; Burke, W J ^[1]; Aggson, T L ^[2]; Basinska, E M ^[3]; Craven, P ^[4]; Peterson, W K ^[5]; Sugiura, M ^[6]; Weimer, D R ^[7]

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1. Air Force Geophysics Lab., Hanscom AFB, MA (USA)
2. Goddard Space Flight Center, Greenbelt, MD (USA)
3. Regis College, Weston, MA (USA)
4. Marshall Space Flight Center, Huntsville, AL (USA)
5. Lockheed Palo Alto Research Lab., CA (USA)
6. Lockheed Palo Alto Research Lab., CA (USA) Tokai Univ., Tokyo (Japan)
7. Univ. of Alaska, Fairbanks (USA)

A broad spectrum of particle and field measurements was taken near local noon by the Dynamics Explorer satellites during the magnetic storm of September 6, 1982. While at apogee, DE 1 sampled the magnetospheric boundary layer at mid southern latitudes and, due to the passage of an intense solar wind burst, briefly penetrated into the magnetosheath. In the boundary layer and the adjacent magnetosheath the plasma flow was directed toward dawn. Variance and de Hoffman-Teller analyses of electric and magnetic field data during the magnetopause crossing showed the magnetopause structure to be that of a rotational discontinuity or an intermediate shock with a substantial normal magnetic field component. This is consistent with an open magnetosphere model in which significant magnetic merging occurs at the local time of the spacecraft. The orbit of DE 2 carried it through the morning sector of the low-altitude, southern cusp. The measurements show a well-defined, cusp current system occurring on open magnetic field lines. At both cusp and subcusp latitudes the electric field was equatorward indicating a strongly eastward plasma flow. The boundary between these two regions was marked by the onset of magnetosheath precipitation and an electric field structure containing both poleward and equatorward spikes. The poleward spike has associated field-aligned currents which are closed by Pedersen currents and, from force balance considerations, is interpreted as the signature of a magnetic merging event at the magnetopause. The equatorward spike has the characteristics of a down-coming and reflected Alfven wave packet of finite dimensions. The high-altitude measurements suggest that the dayside boundary layer is made up of closed magnetic flux tubes, a large fraction of which drift to the magnetopause where merging with the IMF occurs.

• OSTI ID: 5310789
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A3; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
BOUNDARY LAYERS
DYNAMICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC FIELDS
ELECTRIC POTENTIAL
EXPLORER SATELLITES
HYDROMAGNETIC WAVES
INTERACTIONS
IONOSPHERE
LAYERS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FLUX
MAGNETIC STORMS
MAGNETOPAUSE
MAPPING
MECHANICS
PLANETARY IONOSPHERES
PLASMA DRIFT
POLAR CUSP
SATELLITES
SOLAR ACTIVITY
SOLAR WIND