Fig. 2. Total radial density profile of Arr resulting from a fleet of orbital transfer vehicles transporting materials for one SPS from low earth orbit to geosynchronous earth orbit. of the initial beam mass (3). Given the large beam injection rates suggested by Table 1, the plasmasphere loading per SPS constructed would result in a 1%-10% number density increase and a two order of magnitude increase in energy density when compared to the naturally occurring cold plasma in this region, in Figure 2 we display the total Ar+ beam deposition per SPS as a function of radial distance from the earth's center L. For comparison the typical plasmasphere density is about 103 cm’3. The lifetimes of deposited beam ions were determined for three mam loss processes: charge exchange, electron coulomb scattering, and pilch angle scattering due to turbulence induced by beam ion anisotropy. Within the plasmasphere, electron coulomb scattering represents the fastest loss process y ielding lifetimes of only about one day near low earth orbit. Near the plasmaspause, however, the lifetime could be montns. Since electron coulomb scattering is sensitive to ambient temperature, if the deposited beam ions give rise to substantial plasmasphere heating then charge exchange could be the dominant loss process below altitudes of about 6000 km. Plasma instabilities driven by the anisotropic Ar+ may give rise to intense turbulence. This turbulence could in turn scatter Ar+ into the atmospheric loss cones where the ions precipitate out. The significance of this effect is determined by how far above the limiting flux level the deposited Ar' ions are. Further research is required to better quantify the expected turbulence levels. The turbulence is very difficult to simulate theoretically and active experiments in space to obtain a final answer as to the magnitude of its effects may be required.
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