Correlated observations of energetic particles upstream of the bow shock, in the magnetosheath, and in the magnetosphere

Journal Article · Sat Dec 01 00:00:00 EST 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA095iA12p21297· OSTI ID:5268629

Scholer, M; Moebius, E; Kistler, L M ^[1]; Ipavich, F M ^[2]

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1. Max-Planck-Institut fuer Physik und Astrophysik, Garching (West Germany)
2. Univ. of Maryland, College Park (USA)

Simultaneous measurements of energetic protons and alpha particles by the ISEE 1 and AMPTE/IRM spacecraft in the region upstream of the Earth's bow shock are reported during the period 0700-0900 UT on October 19, 1984. IRM observes a diffuse distribution over the whole two hour period. In the spacecraft frame an anisotropy exists with more particles streaming toward the bow shock. ISEE 1 observes occasional bursts of energetic ions which exhibit a beam like distribution along the magnetic field away from the bow shock. The occurrence of these beams is in most cases correlated with a change of the longitudinal interplanetary magnetic field direction, such that a field line from the position of the spacecraft meets the shock with a smaller angle between magnetic field and shock normal. The differential intensity at IRM is about one order of magnitude higher than at ISEE 1. Simultaneously measured spectra by AMPTE/CCE within the magnetosphere close to the magnetopause are considerably harder than the spectra at both upstream locations. A comparison of a CCE spectrum in the magnetosheath with an upstream IRM spectrum shows that the proton intensity observed just outside of the magnetopause between 15 and 80 keV is lower than the upstream spectrum. In the magnetosheath the protons stream away from the bow shock toward the magnetopause and the anisotropy increases with energy. Predictions of the magnetospheric leakage model and of the bow shock acceleration model are compared, and it is shown that the observations are consistent with bow shock acceleration, whereas there are extreme difficulties with an explanation in terms of magnetospheric leakage.

• OSTI ID: 5268629
• Journal Information: Journal of Geophysical Research; (United States), Vol. 95:A12; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH MAGNETOSPHERE
SOLAR WIND
INTERACTIONS
ACCELERATION
ALPHA PARTICLES
ANISOTROPY
COMPARATIVE EVALUATIONS
CORRELATIONS
INTERPLANETARY MAGNETIC FIELDS
INTERPLANETARY SPACE
LEAKS
MAGNETOPAUSE
MAGNETOSHEATH
MASS TRANSFER
MATHEMATICAL MODELS
ORIGIN
PROTONS
REFLECTION
SATELLITES
BARYONS
CHARGED PARTICLES
EARTH ATMOSPHERE
ELEMENTARY PARTICLES
EVALUATION
FERMIONS
HADRONS
MAGNETIC FIELDS
NUCLEONS
SOLAR ACTIVITY
SPACE
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena