Generation of broadband electrostatic noise by ion beam instabilities in the Magnetotail

Journal Article · Fri Jun 01 04:00:00 EDT 1984 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA089iA06p03865· OSTI ID:6858970

Grabbe, C L; Eastman, T E

Particle data from ISEE 1 sampled in the earth's magnetotail show the presence of energetic ion beams in the boundary layer of the plasma sheet. A theory of instabilities driven by the beams is developed and compared with wave data sampled simultaneous to the particle data. We conclude that ion beams generate broadband electrostatic bursts of noise. The electrostatic noise correlates well with the occurrence of the beams, and the spectrum is consistent with that predicted from a negative energy beam instability under magnetotail conditions. The theory predicts that a spectrum of growing wves can be driven for frequencies from 0.001 ..omega../sub p//sub e/ up to ..omega../sub p//sub e/, the electron plasma frequency, with a spectral peak typically near 0.01 ..omega../sub p//sub e/ or lower, in agreement ith the wave data. Furthermore, as one moves away from the source region perpendicular to the magnetic field, the high-frequency components of the observed wave spectra are predicted to disappear gradually, leaving the low-frequency part of the spectrum, also as is observed. Evidence is given for significant pitch angle scattering of the beams by the broadband electrostatic noise leading to more isotropic ion distributions.

• Research Organization: Department of Physics and Astronomy, University of Iowa
• OSTI ID: 6858970
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 89:A6; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BEAMS
BOUNDARY LAYERS
EARTH ATMOSPHERE
INSTABILITY
ION BEAMS
ION WAVE INSTABILITY
LAYERS
MAGNETOSPHERE
MAGNETOTAIL
NOISE
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
PLASMA SHEET
PLASMA WAVES