On the source of diffuse, suprathermal ions observed in the vicinity of the Earth's bow shock

Journal Article · Sat Apr 01 04:00:00 EST 1989 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA094iA04p03555· OSTI ID:6271839

Gosling, J T; Thomsen, M F; Bame, S J; Russell, C T

Using the fast plasma experiment (FPE) data from ISEE 2, we have searched for ''diffuse,'' suprathermal ion events that occurred when the interplanetary magnetic field was nearly radial and when the spacecraft was upstream from the Earth's bow shock at local times greater than 1530. For such conditions the field lines sampled should not approach closer than /similar to/4 R/sub E/ to the Earth's magnetopause according to present models of the flow of the solar wind around the magnetosphere. A number of diffuse ion events satisfying these selection criteria have been found, two of which are described in detail in this paper. At energies below 40 keV (the highest energy sampled by the FPE) these events are representative of the vast majority of diffuse ion events detected by the FPE independent of field orientation and local time. In particular, the events are observed in association with large-amplitude, low-frequency magnetic field fluctuations; the suprathermal particle velocity distributions are roughly isotropic in the solar wind frame; and the spectra appear to extend smoothly to energies beyond 40 keV. Owing to the special field geometry selected for these events, it is highly unlikely that the events studied could be the result of leakage of suprathermal ions from the magnetosphere. Rather, the suprathermal ions are almost certainly accelerated out of the solar wind by processes operating in the vicinity of the bow shock. The fact that these specially selected events have characteristics that are typical of diffuse ion events in general as observed by the FPE suggests that shock processes are the prime cause of diffuse ion events observed in the vicinity of the bow shock at energies below 40 keV. copyright American Geophysical Union 1989

• Research Organization: Los Alamos National Laboratory, University of California, Los Alamos, New Mexico
• OSTI ID: 6271839
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 94:A4; 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
ACCELERATION
CHARGED PARTICLES
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
INTERPLANETARY MAGNETIC FIELDS
ION TEMPERATURE
IONS
MAGNETIC FIELDS
MAGNETOPAUSE
PLASMA ACCELERATION
SOLAR ACTIVITY
SOLAR WIND