Linear instabilities in multicomponent plasmas and their consequences for the auroral zone

Journal Article · Fri Apr 01 04:00:00 EST 1988 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA093iA04p02633· OSTI ID:5190306

Schriver, D; Ashour-Abdalla, M

Ion conics are commonly observed along auroral zone field lines and involve all major terrestrial ion species, including hydrogen, helium, and oxygen. It is believed that low-frequency plasma waves, driven unstable by field-aligned currents, transversely heat the ion distributions via wave-particle interactions, creating the ion conics. Considered here are low-frequency, oblique, electrostatic instabilities found in a mixed plasma that includes an electron beam streaming through a background of electrons, hydrogen, and oxygen. The addition of oxygen not only modifies the lower hybrid frequency, but allows the existence of an ion-ion (Buchsbaum) hybrid mode with a frequency between the hydrogen and oxygen gyrofrequencies. Because of its low frequency, the ion-ion hybrid instability can be effective in transversely heating heavy ions. When the electron beam drift speed is greater than 3 times the background electron thermal velocity (V/sub 0/>3v/sub te/) and the electron gyrofrequency to plasma frequency ratio is less than 10 (..cap omega../sub e/..omega../sub pe/<10), the lower hybrid instability dominates. However, for ..cap omega../sub e/..omega../sub pe/>20, which is a condition commonly found in the auroral zone nightside region, the ion-ion instability has the largest growth rates; in these regions, heavy ion transverse heating can occur. When 10<..cap omega../sub e/..omega../sub pe/<20 the hydrogen to oxygen density ratio determines which instability dominates. copyright American Geophysical Union 198

• Research Organization: Department of Physics, University of California at Los Angeles
• OSTI ID: 5190306
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 93:A4; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
BEAMS
ELECTRON BEAMS
ELEMENTS
FLUIDS
GASES
HELIUM
HYDROGEN
INSTABILITY
ION PLASMA WAVES
ION TEMPERATURE
ION WAVES
IONIC COMPOSITION
LEPTON BEAMS
NONMETALS
OXYGEN
PARTICLE BEAMS
PLASMA INSTABILITY
PLASMA WAVES
RARE GASES