Interaction of upgoing auroral H/sup +/ and O/sup +/ beams

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · J. Geophys. Res.; (United States)

OSTI ID:5086694

Kaufmann, R L; Ludlow, G R; Collin, H L; Peterson, W K; Burch, J L

Data from the S3-3 and DE 1 satellites are analyzed to study the interaction between H/sup +/ and O/sup +/ ions in upgoing auroral beams. Every data set analyzed showed some evidence of an interaction. The measured plasma was found to be unstable to a low-frequency electrostatic wave that propagates at an oblique angle to B-arrow-right/sub 0/. A second wave, which can propagate parallel to B-arrow-right/sub 0/, is weakly damped in the plasma studied in most detail. It is likely that the upgoing ion beams generate this parallel wave at lower altitudes. The resulting wave-particle interactions qualitatively can explain most of the features observed in ion distribution functions. H/sup +/ ions in the low-velocity tail of the H/sup +/ beam are decelerated and O/sup +/ ions in the high-velocity tail of the 0/sup +/ beam are accelerated through this process. This may explain the occasional observation of O/sup +/ beams with substantially higher streaming energies than the simultaneously observed H/sup +/ beams. The wave-particle interactions also can explain the asymmetrical features that regularly are seen in H/sup +/ and 0/sup +/ distribution functions. The wave which was found to be unstable in the measured plasma primarily accelerates 0/sup +/ perpendicular to B/sub O/. This process can produce weakly conical 0/sup +/ distributions which are characterized by T/sub perpendicular/>T/sub Pi/ rather than by having a peak at 90/sup 0/ pitch angle within the acceleration region. In general, the interaction between different ion species in multicomponent beams appears to be a dominant factor in determining the structure of upgoing auroral ions. The same process is likely to be important in a number of other beam-containing space plasmas.

• Research Organization: Department of Physics, University of New Hampshire
• OSTI ID: 5086694
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 91:A9; 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
ACCELERATION
AURORAE
BEAMS
CATIONS
CHARGED PARTICLES
DISTRIBUTION FUNCTIONS
EARTH ATMOSPHERE
EXPLORER SATELLITES
FUNCTIONS
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
ION BEAMS
ION DENSITY
ION TEMPERATURE
IONOSPHERE
IONS
OXYGEN IONS
PLANETARY IONOSPHERES
PLASMA ACCELERATION
PLASMA WAVES
SATELLITES