The flow configuration of protons and alpha particles in the Earth's subsolar magnetosheath

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5814139

Greene, E A

Attempts were made to experimentally determine whether the magnetosheath bulk flow has a stagnation point or a stagnation line configuration, using data from the Active Mesospheric Particle Tracer Explorer (AMPTE)/Charge Composition Explorer (CCE) Spacecraft. The AMPTE/CCE spacecraft has an equatorial orbit with an apogee of 8.8 R sub 3. During compressions of the magnetosphere, it enters the subsolar magnetosheath, sometimes for several hours. This is an ideal situation to observe the flow configuration because the spacecraft is at rest, or nearly so, in the subsolar region. The CHEM instrument can detect ions from 1 to 300 keV/e in approximately the YZ GSE plane, the plane parallel to the magnetopause. Near the subsolar region, most of the bulk flow speed is in this plane. The H(+) and He(+2) is approximately 20 percent lower than that of the H(+) on average, although this may be a computational artifact. The bulk flow direction was compared to the theoretical flow direction predictions for a stagnation point and a stagnation line. It was found that 36 percent of the time intervals were consistent with the theory of a stagnation point, while 24 percent of the intervals were consistent with the theory of a stagnation line. The hourly average interplanetary magnetic field from the IMP 8 spacecraft was examined during the orbits for which it was available. For orbits with a significant number (greater than 4) of stagnation point-like intervals, the interplanetary magnetic field (IMF) was either northward or unmeasured. In contrast, for stagnation line-like orbits the IMF was either southward or unmeasured. The flow configuration of the subsolar magnetosheath appears to be fundamentally different for different orientations of the IMF.

• Research Organization: Maryland Univ., College Park, MD (United States)
• OSTI ID: 5814139
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALPHA PARTICLES
BARYONS
CHARGED PARTICLES
DATA
ELEMENTARY PARTICLES
EXPERIMENTAL DATA
FERMIONS
FLUID MECHANICS
HADRONS
HELIUM IONS
HYDRODYNAMICS
HYDROGEN IONS
INFORMATION
INTERPLANETARY MAGNETIC FIELDS
ION DRIFT
IONS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MAGNETOSHEATH
MECHANICS
MOTION
NUCLEONS
NUMERICAL DATA
PARTICLE KINEMATICS
PROTONS
STAGNATION