Alternative interpretation of ion ring distributions observed by the S3-3 satellite

Journal Article · Sun May 01 04:00:00 EDT 1983 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL010i005p00417· OSTI ID:5910391

Gorney, D J

Recently, theoretical interest has grown in possible plasma wave instabilities arising from free energy in auroral ion distributions, and a number of ion-mode instabilities have been identified. These instabilities typically rely on positive slopes in the ion's velocity distribution parallel (partialf/partialv/sub parallel/>0) or perpendicular (partialf/partialv/sub perpendicular/>0) to the magnetic field. Upflowing ion beams generated by electrical potential drops along auroral field lines are obvious candidates for the parallel (beam) instability, while ion conics have been treated in the limit of the flute mode instability, assuming that a positive perpendicular gradient exists. However, ion conics are not responsible for the condition partialf/partialv/sub parallel/>0. Downflowing ion beam distribution can have partialf/partialv/sub perpendicular/>0 and therefore might lead to flute mode instability. Examples of both conics and downflowing beams are presented showing that only the downflowing component leads to signficant partialf/partialv/sub perpendicular/>0, while ion conics generally have partialf/partialv/sub parallel/<0 and are themselves stable to the flute mode.

• Research Organization: Space Sciences Laboratory, The Aerospace Corporation, P.O. Box 92957, Los Angeles, CA 90009
• OSTI ID: 5910391
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 10:5; ISSN GPRLA
• 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
DISTRIBUTION FUNCTIONS
ELECTRIC FIELDS
FLUTE INSTABILITY
FUNCTIONS
INSTABILITY
ION BEAMS
ION WAVE INSTABILITY
ION WAVES
MAGNETIC FIELDS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA MICROINSTABILITIES
PLASMA WAVES