Correlation between proton anisotropy and magnetic field direction in the distant geotail

Journal Article · Mon Oct 01 04:00:00 EDT 1984 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL011i010p01038· OSTI ID:6213483

Klecker, B; Scholer, M; Hovestadt, D; Gloeckler, G; Ipavich, F M; Smith, E J; Tsurutani, B T

We report the results of a statistical analysis of the anisotropy of suprathermal protons and of the polarity of the magnetic field during the time period April 10--16, 1983, when the ISEE-3 spacecraft was at lunar distances (approx.61-78 radii) in the geomagnetic tail of the earth, well within the nominal magnetopause. Using 128 sec time averages of the angular distributions of 33 keV protons, we correlate the first order anisotropy with the latitude angle, theta, and the z-component, B/sub Z/, of the magnetic field. We find that the frequency distribution of the anisotropy direction, in particular for large anisotropies, is strongly peaked in the earthward and tailward direction, indicative of fast earthward and tailward flows. For large anisotropies and within 5 R/sub E/ (earth radii) of the nominal neutral sheet position we find a strong correlation of earthward streaming suprathermal protons with northward polarity of the magnetic field whereas large tailward anisotropies are generally correlated with southward magnetic field polarity. The simplest interpretation of this correlation is in terms of a neutral line (or reconnection) model, with the neutral line being tailward or earthward of the spacecraft, respectively.

• Research Organization: Max-Planck-Institut fuer Physik and Astrophysik, Institut fuer extraterrestrische Physik, 8046 Garching, FRG
• OSTI ID: 6213483
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 11:10; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANGULAR DISTRIBUTION
ANISOTROPY
BARYONS
DISTRIBUTION
EARTH ATMOSPHERE
ELEMENTARY PARTICLES
EXPLORER SATELLITES
FERMIONS
GEOMAGNETIC FIELD
HADRONS
MAGNETIC FIELDS
MAGNETOSPHERE
MAGNETOTAIL
NUCLEONS
PROTONS
SATELLITES