Generation of broadband noise in the magnetotail by the beam acoustic instability

Journal Article · Sat Nov 01 04:00:00 EST 1986 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA091iA11p12005· OSTI ID:6984190

Dusenbery, P B

Analytic properties of the ion beam acoustic instability are evaluated for reasonable magnetotail conditions and are found to be consistent with observations of broadband turbulence not only in the plasma sheet boundary layer but also in the lobes and central plasma sheet regions. Numerical calcualtions confirm many of the analytic results. Specifically, the dependence of the ion beam acoustic mode on particle distribution models is investigated. Without cold ions present the acoustic mode is stable. With cold streaming ions present the acoustic mode is unstable, but the growth rate is significantly enhanced when warm streaming boundary layer ions are simultaneously present. These results suggest that the interaction between the warm and cold ions streams is responsible for the peak in the electrostatic wave intensities observed within the plasma sheet boundary layer. In addition, the beam acoustic instability, for magnetotail models, is found to be due to resonant, not nonresonant, interactions. Relative streaming effects and dependence on ion species are considered and found to play significant roles in the behavior of beam acoustic growth as a function of wave normal angle and wave number.

• Research Organization: Department of Astrophysical, Planetary, and Atmospheric Sciences, University of Colorado, Boulder
• OSTI ID: 6984190
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 91:A11; 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
BEAMS
BOUNDARY LAYERS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
INSTABILITY
ION ACOUSTIC WAVES
ION BEAMS
ION DENSITY
ION TEMPERATURE
ION WAVES
LAYERS
MAGNETOTAIL
MATHEMATICAL MODELS
NOISE
PLASMA SHEET
PLASMA WAVES
TURBULENCE