Accession Number : ADA111741

Title :   Plasmaspheric Helium Ion Distribution from Satellite Observations of HeII 304 A,


Personal Author(s) : Chiu,Yam T ; Chakrabarti,Supriya ; Paresce,Francesco ; Bowyer,Stuart ; Aikin,Arthur

PDF Url : ADA111741

Report Date : 07 Jan 1982

Pagination or Media Count : 23

Abstract : High sensitivity and spatial resolution observations of the He(2)II-304 A emission line intensity in the earth's nightglow have been carried out by the extreme ultraviolet telescope on the Apollo-Soyuz mission in July 1975. The data, obtained over a wide range of parameters, are compared with the predictions of a kinetic equilibrium model of plasmaspheric ion density. Excellent overall agreement observation and theory is found using as inputs a temperature model, solar flux, and H+ and O+ number densities determined by extrapolating nearly simultaneous Atmospheric Explorer C measurements at 300 km. The observations in the northern hemisphere are well fit by a model having 285 He+ ions cm-3 at 500 km independent of latitude or longitude while those in the south require 430 He+ ions cm -3 at the same altitude. This result is consistent with available information on the interhemispheric asymmetry of He+ observed by a mass spectrometer on Explorer 32 and on the winter neutral helium bulge. (Author)

Descriptors :   *Emission spectra, *Helium, *Air flow, *Night, Earth(Planet), Ultraviolet radiation, Space systems, Asymmetry, Hemispheres, Atmospheric physics, Atmospheric chemistry, Ion density, Atmosphere models, Mathematical models

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE