Observations of polar ion outflows

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA02180· OSTI ID:5314705

Chandler, M O; Moore, T E ^[1]; Waite, Jr, J H ^[2]

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1. NASA George C. Marshall Space Flight Center, Huntsville, AL (USA)
2. Southwest Research Inst., San Antonio, TX (USA)

The characteristics of the polar ion outflows as observed in the topside polar ionosphere by the Dynamics Explorer Retarding Ion Mass Spectrometer are reported in this study. The study is restricted to altitudes between 1,000 and 4,000 km in order to focus on the phenomenon of the classical polar wind. Except insofar as they convect into the polar cap at these altitudes, auroral and cusp/cleft outflows are specifically excluded from this study. Using a method based on the relative wind of ions as seen from the moving spacecraft, averages and variances of the magnetic field-aligned ion flux and velocity, and the species densities, are derived and binned for examination of their altitudinal, seasonal, and magnetic activity dependencies. The data set used encompasses the period from autumn 1981 through 1983, the altitude range from 1,000 to 4,000 km, and invariant latitudes greater than 70{degree}. Observations of H{sup +}, He{sup +}, and O{sup +} with energies down to spacecraft potential are reported. It is found that the polar outflows are not well correlated with common indicators of solar or geomagnetic activity. The average parameters of the outflows exhibit a winter enhancement of He{sup +} flux, a winter decrease in H{sup +} flux, and a summer enhancement of the asymptotic outflow speeds of all species. The solar F{sub 10.7} (and hence EUV) flux is correlated with the acceleration profile of the flows, with slower flow velocities at 2,500 km altitude for active solar conditions. Evidence is found that the H{sup +} flows are, at times, subsonic in the altitude range studied, in contrast to cold polar wind models.

• OSTI ID: 5314705
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A2; ISSN 0148-0227; 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
ALTITUDE
BARYONS
CHARGED PARTICLES
CORRELATIONS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELEMENTARY PARTICLES
EXPLORER SATELLITES
FERMIONS
HADRONS
HELIUM IONS
ION DENSITY
ION DRIFT
IONOSPHERE
IONS
MAGNETIC FIELD CONFIGURATIONS
MAGNETOTAIL
MATHEMATICAL MODELS
NUCLEONS
OXYGEN IONS
PLANETARY IONOSPHERES
POLAR REGIONS
PROTONS
SATELLITES
SOLAR FLUX
VELOCITY