CHARGE-EXCHANGE LIFETIMES FOR LOW-ENERGY PROTONS IN THE OUTER RADIATION ZONE AND IMPLICATIONS CONCERNING THE DENSITY OF ATOMIC HYDROGEN IN THE TERRESTRIAL EXOSPHERE,
Abstract
The directional, differential intensities of protons over the energy range of about 200 eV to 50 keV injected into the outer radiation zone (i.e., the extraterrestrial ring current) coincident with the initial phase of the geomagnetic storm during early July 1966 were monitored with a sensitive array of electrostatic analyzers borne on the earth-satellite OGO 3. Proton intensities are greatly enhanced throughout the outer radiation zone for L-values approximately equal or > 3 during the main phase of this moderate magnetic storm, and the injection mechanism ceases to be effective after the storm main phase for L-values approximately equal or < 5.5. The proton (30 = or < E = or < 50 keV) intensities are shown to exponentially decay with lifetimes ranging from 15 to 105 hours in substantial agreement with calculated lifetimes invoking measured charge-exchange cross-sections for protons incident upon atomic hydrogen and a model of the atomic hydrogen density in the earth's exosphere. The atomic hydrogen density model for the terrestrial exosphere providing the best fit to the observed proton lifetimes over geocentric radial distances 2.5 to 4.8 earth radii (corresponding to observed densities of about 200 to 30 hydrogen atoms/cc) allows only atoms in ballistic orbits in the exosphere as opposed to a model geocorona which includes an additional atomic hydrogen population in captive elliptical orbits. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1968
- Accession Number
- AD0666964
Entities
People
- Louis A. Frank
- R. L. Swisher
Organizations
- University of Iowa