spatially irregular plasma created then has roughly the same lifetime for either source and the effects on radio waves may be expected to be similar, although at different geographical locations. In Figure 3, we show a map of the western hemisphere with the near surface L values projected from the earth's equatorial plane (16). Since precipitation is expected between L = 1.1 low earth orbit and L~ 4.0 (plasmapause), most of effects will occur over a latitude range which is roughly centered about the continental U.S. In Figures 4a and 4b (17) we show the spatial distribution of energetic radiation belt protons for E > 50 MeV and E > 0.4 MeV which may be precipitated. We may estimate the lifetime of the radiation belt protons in the plasma turbulence generated by the Ar+ using the expressions developed by Curtis and Grebowsky (3). Noting that the bounce times are 0.5 to 1 sec for the MeV energy protons and taking the number of bounce periods required to isotropize the MeV ions as about the same as that of the Ar+, depletion of radiation belt protons can occur up to two orders of magnitude faster than the Ar+. We may then expect substantial fluxes of radiation belt protons to precipitate before the Ar+ turbulence subsides due to the Ar+ population's approach to a limiting flux condition. As the Ar* beam propagates outward during the orbital transfer vehicle’s trip to geosynchronous earth orbit a continuous source of anisotropic Ar+ will exist extending from the orbital transfer vehicle’s orbit to the plasmapause. Thus precipitation effects will extend over the lifetime of the SPS construction (—6 months/station). In addition to the pr.oton precipitation, Ar+ precipitation due to plasma turbulence may be expected as well as the ionization effects due to precipitating —5 keV argon neutral atoms resulting from charge exchange. Also, direct precipitation will occur at orbits near low earth orbit due to the ion beam velocity spread. The penetration depth of the energetic ions will range from stratospheric altitudes for the more energetic radiation belt protons to mesospheric-thermospheric altitudes for the energetic Ar+ and Ar (18). We note that even if only 0.01% of the deposited beam energy is converted to plasma turbulence (19) the expected wide band wave amplitude characterizing this turbulence will be — 10' my which is much greater than the natural wave amplitudes observed closely confined to the earth’s magnetic equatorial plane of —20 my (15). The turbulence amplitudes are less than 1% of the ambient magnetic field. Thus a 3 order of magnitude enhancement of plasma wave turbulence above its natural maximum level may be possible. The stated beam energy to plasma turbulence conversion is meant to be suggestive of the possible effect’s magnitude. The reduction of this number by orders of magnitude would still produce significant effects. We also note that the number used for conversion efficiencies is considerably less than that deduced from observations of plasma instability processes in other papers in the literature (20). The possible high levels of turbulence are consistent with our conclusion that greatly increased ion precipitation may be expected. This expectation is also in agreement with the recent results of the Cameo experiments that involved the release of large quantities of Ba into the magnetosphere (J. P. Heppner, private communication) which may have triggered auroral type particle precipitation. These experiments are known to have produced much greater than normal rf scintillations and signal attenuation as determined from monitoring a pass of the U.S. satellite GEOS-3. This scintillation and attenuation is precisely the type of communication impairment expected from the Ar+ induced precipitation. Ionospheric scintillation will be produced by ionospheric electron density inhomogenities due to the spatial
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