which 1.54 <= L <= 5.64; ions for which L <= 1.40 and L >= 5.78 would be outside the orbiting gas cloud and experience no enhancement over the natural neutralgas density. Calculations by Farley and Walt (1971) yield a natural gas density (H plus He) of 3200 cm-3 at L = 1.5, 628 cm-3 at L = 1.9, and 225 cm-3 at L = 2.5 as an average over the solar cycle. Their solar-minimum model led to densities of 2761 cm-3, 922 cm-3, and 309 cm-3 at the three L values, and their solar-maximum model yielded densities of 5130 cm-3, 611 cm-3, and 197 cm-3. The above results suggest that our orbiting cloud of neutrals due to a single POTV mission would not significantly reduce the Coulomb lifetimes of the famous 10-100 MeV inner belt protons (L [[spi:math]] 2) that are derived from the decay of cosmic-ray-albedo neutrons. The added density of 127 atoms/cm3 is just too small a fraction of the natural atomic density to make a major contribution to the loss process there. It would take at least four POTV flights to double the natural atomic density at L = 1.9, for example. At a gas densi- ty of 127 cm-3, we have found that a 1-MeV proton would lose only 4 x 10 -5 MeV/day, or about 15 keV/year. The rate of energy loss is even smaller at higher energies. Moreover, the L = 1.9 drift shell lies in the outer part of the inner proton belt, and other transport processes are believed to be more important than Coulomb loss there. It is at the center of the belt (perhaps L = 1.5) where Coulomb loss seems to play a major dynamical role, and there the natural atomic density is twenty to forty times the density of our orbiting neutral cloud, which barely extends to such a low L value in any case. The variation of natural atomic densities with L suggests that our neutral cloud would be of dynamical significance on the ionic ring current, which resides at higher L values than the inner proton belt. Tinsley (1976) uses a density estimate [[spi:math]] 700 cm-3 for natural atomic hydrogen at L = 3 (this being 69
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