DE-1 observations of polar O(+) stream bulk parameters and comparison with a model of the centrifugally-accelerated polar wind

Technical Report · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:102040

Ho, C W; Horwitz, J L

A survey of bulk parameters of analyzable O(+) outward streams in the mid-altitude (3-4.7 R(sub E) geocentric distance) polar cap magnetosphere is obtained from measurements by the Retarding Ion Mass Spectrometer (RIMS) aboard the Dynamics Explorer-1 (DE-1) spacecraft. There is wide scatter in the obtained densities, but they do display discernible trends: the average O(+) density in these streams decreases from about 60 ions/cc at 3.5 R(sub E) to about 1 ion/cc at 4.6 R(sub E). The streaming velocities are somewhat more defined, and their average increases from about 8 km/s at 3.5 R(sub E) to about 12 km/s at 4.6 R(sub E). The densities and bulk velocities are inversely correlated. The authors have further compared these observational trends with model profiles for the centrifugally-accelerated polar wind as recently described by Horwitz et al.. The large outflow velocities observed can be understood in part as centrifugally-driven by convection with ionospheric electric field magnitudes of the order 50-70 mV/m, perhaps including plasma expansion effects.

• Research Organization: National Aeronautics and Space Administration, Huntsville, AL (United States). George C. Marshall Space Flight Center
• OSTI ID: 102040
• Report Number(s): N--95-31743; NASA-CR--198930; NAS--1.26:198930; CNN: NAG8-134; NAG8-822; NAG1-554; RTOP 432-20-00
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CONVECTION
EARTH MAGNETOSPHERE
FLUX DENSITY
OXYGEN IONS
POLAR REGIONS
VELOCITY