Abstract
A computer simulation of the sputtering of lunar soil by solar wind protons was performed with the TRIM program. The rate of the sputtering-induced erosion of regolith particles was shown to be less than 0.2 Å per year. A preferential sputtering of Ca, Mg, and O was found along with a less intense sputtering of Fe, Si, and Ti. However, with no other selection mechanisms, surface concentrations of the atoms would differ from the volume ones by no more than 6 %. The enrichment of rims of regolith particles with iron occurs as a result of selective removal of lighter atoms from the lunar surface because of different energies of escape from the Moon's gravity. The energy distributions proved to be the same for all sorts of the sputtered atoms, except for implanted hydrogen; thus, a greater fraction of the atoms left on the lunar surface corresponds to heavier elements. According to simulation results, the concentration of reduced iron observed in the mature regolith could be attained during the time of regolith particle exposure to the present flux of solar wind (105 years). Thus, sputtering can provide the concentration of Fe0 observed in regolith. On periphery of a cloud of impact vapor the temperature is too low for an irreversible selective removal of evaporation products; thus, a meteoritic bombardment contributes to the formation of composition of the rims of regolith particles mainly through enrichment of the rims with elements from the bulk of the particles. The estimates of fluxes of backscattered solar wind protons and of sputtered protons, earlier implanted to the regolith, demonstrated that their contribution to the proton flux near the poles is only 104 cm–2 s–1. This is by two orders of magnitude smaller than the proton flux from the Earth's magnetosphere which is, therefore, the main source of protons for permanently shaded polar craters of the Moon.
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REFERENCES
Andersen, H.H. and Bay, H.L., Sputtering Yield Measurements, in Sputtering by Particle Bombardment. I, Behrish, R., Ed., Berlin: Springer, 1981, pp. 145–218. Translated under the title Raspylenie tverdykh tel ionnoi bombardirovkoi, Moscow: Mir, 1984, pp. 194-280.
Bazilevskii, A.T., Ivanov, B.A., Florenskii, K.P., et al., Udarnye kratery na Lune i planetakh (Impact Craters on the Moon and Planets), Moscow: Nauka, 1983.
Bernatowicz, T.J., Nichols, R.H., Jr., Hohenberg, C.M., and Maurette, M., Vapor Deposits in the Lunar Regolith: Discussions and Reply, Science, 1994, vol. 264, pp.? 1779–1780.
Betz, G. and Wehner, G.K., Sputtering of Multicomponent Materials, in Sputtering by Particle Bombardment. II, Behrish, R., Ed., Berlin: Springer, 1983, pp. 11–90. Translated under the title Raspylenie tverdykh tel ionnoi bombardirovkoi. II, Moscow: Mir, 1986, pp. 24-133.
Biersack, J.P. and Haggmark, L.G., A Monte Carlo Computer Program for the Transport of Energetic Ions in Amorphous Target, Nucl. Instr. Methods, 1980, vol. 174, pp.?257–269.
Biersack, J.P., Computer Simulation of Sputtering, Nucl. Instr. and Methods. Phys. Res., 1987, vol. B27, pp. 21–36. Translated under the title Fundamental'nye i prikladnye aspekty raspyleniya tverdykh tel (Fundamental and Applied Aspects of Sputtering of Solid Bodies), Moscow: Mir, 1989, pp. 88-125.
Borg, J., Comstick, G.M., Langevin, Y., et al., A Monte Carlo Model for the Exposure History of Lunar Dust Grains in the Ancient Solar Wind, Earth Planet. Sci. Lett., 1976, vol. 29, pp. 161–174.
Crider, D.H. and Vondrak, R.R., The Solar Wind as a Possible Source of Lunar Polar Hydrogen Deposits, J. Geophys. Res. E, 2000, vol. 105, pp. 26773–26782.
Des Marais, D.J., Hayes, J.M., and Meinschein, W.G., The Distribution in Lunar Soil of Hydrogen Release, Tucson: LPI, 1974, vol. 2, pp. 1811–1822.
Dikov, Yu.P., Bogatikov, O.A., Barsukov, V.L., et al., Some Features of the Main Element Conditions in Surface Layers of the Regolith Particles in the Luna Automatic Stations Samples: XPS Studies, Proc. 9th Lunar Planet. Sci., 1978, pp. 2111-2124.
Dikov, Yu.P., Bogatikov, O.A., Nemoshkalenko, V.V., et al., Specific State of Rock-forming Elements in Surface Layers of the Regolith Particles in Luna-24 Samples, Geokhimiya, 1977, no. 10, pp. 1524-1533.
Feldman, W.C., Lawrence, D.J., Elphic, R.C., et al., Polar Hydrogen Deposits on the Moon, J. Geophys. Res. E, 2000, vol. 105, pp. 4175–4195.
Gold, T., Bilson, E., and Baron, R.L., Auger Analysis of the Lunar Soil: Study of Process Which Changes the Surface Chemistry and Albedo, Proc. 6th Lunar Sci. Conf., 1975, pp. 3285–3303.
Gruen, D.M., Siskind, B., and Wright, R.B., Chemical Implantation, Isotopic Trapping Effects, and Induced Hydroscopicity Resulting from 15-KeV Ion Bombardment of Sapphire, J. Chem. Phys., 1976, vol. 65, no. 1, pp. 363–378.
Hapke, B., Darkening of Silicate Rock Powders by Solar Wind Sputtering, Moon, 1973, vol. 7, no. 3/4, pp. 342–355.
Hapke, B. and Cassidi, W., Vapor Deposits in the Lunar Regolith; Discussions and Reply, Science, 1994, vol.?264, pp. 1779–1780.
Hardy, D., Hills, H., and Freeman, J., A New Plasma Regime in the Distant Geomagnetic Tail, Geophys. Res. Lett., 1975, vol. 2, pp. 169–178.
Housley, R. and Grant, R., ESCA Studies of Lunar Surface Chemistry, Proc. 6th Lunar Sci. Conf., 1975, pp. 3269-3275.
Housley, R. and Grant, R., ESCA Studies of the Surface Chemistry of Lunar Fines, Proc. 7th Lunar Sci. Conf., 1976, pp. 881-889.
Keller, L.P. and McKay, D.S., Vapor Deposits in the Lunar Regolith; Discussions and Reply, Science, 1994, vol. 264, pp. 1779–1780.
Keller, L.P., Wentworth, S.J., and McKay, D.S., Surface Correlated Nanophase Iron Metal in Lunar Soils: Petrography and Space Weathering Effects, New Views of the Moon, Houston: LPI, 1998, Abstract no. 6033.
Kondrashov, A.P. and Shestopalov, E.V., Osnovy fizicheskogo eksperimenta i matematicheskaya obrabotka rezul'tatov izmerenii (Basics of Physical Experiment and Mathematical Treatment of Measurement Results), Moscow: Atomizdat, 1977.
Lebedinets, V.N., Aerozol' v verkhnei atmosfepe i kosmicheskaya pyl' (Aerosol in the Upper Atmosphere and Cosmic Dust), Leningrad: Gidpometeoizdat, 1981.
Mattern, P.L., Thomas, G.J., and Bauer, W., Hydrogen and Helium Implantation in Vitreous Silica, J. Vac. Sci. Technol., 1976, vol. 13, no. 1, pp. 430–436.
McKay, D.S., Heiken, G., Basu, A., et al., The Lunar Regolith, in Lunar Sourcebook, Heiken, G.H., Vaniman, ?D.T., and French, B., Eds., Moscow: Cambridge Univ. Press, 1991, pp. 285–356.
Morris, R., Surface Exposure Indices of Lunar Soils: a Comparative FMR Study, Proc. 7th Lunar Planet. Sci. Conf., 1976, pp. 315-335.
Morris, R., Origins and Evolution of Grain-Size Dependence of the Concentration of Fine-Grained Metal in Lunar Soils: the Maturation of Lunar Soils to a Steady-State Stage, Proc. 8th Lunar Planet. Sci. Conf., 1977, pp.? 3719-3747.
Morris, R., Origins and Size Distribution of Metallic Iron Particles in Lunar Regolith, Proc. Lunar Planet. Sci. XI, 1980, pp. 1697-1712.
Nefedov, V.I., Sergushin, N.P., Salyn', Ya.V., et al., XPS Studies of Iron and Surface Characteristics of Lunar Regolith from Mare Crisium, in Lunnyi grunt iz Morya Krizisov (Lunar Soil from Mare Crisium), Moscow: Nauka, 1980, pp. 318–324.
Sigmund, P., Sputtering by Ion Bombardment: A General Theoretical View, in Sputtering by Particle Bombardment, I, New York: Springer, 1981. Translated under the title Raspylenie tverdykh tel ionnoi bombardirovkoi, Moscow: Mir, 1984, pp. 23-98.
Siskind, B., Gruen, D.M., and Varma, K., Chemical Implantation of 10-KeV H+ and D+ in Rutile, J. Vac. Sci. Technol., 1977, vol. 14, no. 1, pp. 537–542.
Stankevich, D.G. and Shkuratov, Yu.G., The Shadowing Effect in Regolith-Type Media: Numerical Modeling, Astron. Vestn., 2000, vol. 34, no. 4, pp. 312–322 [Sol. Syst. Res. (Engl. transl.), 2000, vol. 34, no. 4, pp. 285-294].
Starukhina, L.V., Water Detection on Atmosphereless Celestial Bodies: Alternative Explanations of the Observations, J. Geophys. Res. E,, 2001, vol. 106, no. E7, pp. 14701–14710.
Starukhina, L.V., Shkuratov, Yu.G., and Skorik, S.K., Spread of Condensation Products in a Regolith-Like Medium: Estimates and Laboratory Modeling, Astron. Vestn., 1999, vol. 33, no. 3, pp. 244–248 [Sol. Syst. Res. (Engl. transl.), 1999, vol. 33, no. 3, pp. 212-215].
Starukhina, L.V., On the Origin of Excess Hydrogen at the Lunar Poles, Astron. Vestn., 2000, vol. 34, no. 3, pp.?215–219 [Sol. Syst. Res. (Engl. transl.), 2000, vol.?34, no. 3, pp. 233-237].
Vaisberg, O.L., Solnechnyi veter, in Fizika kosmosa (Physics of Space), Moscow: Sovetskaya Entsiklopedia, 1986, pp. 636–639.
Vinogradov, F.P., Nefedov, V.I., Urusov, V.S. et al., XPS Study of Lunar Regolith from Mare Fequnditatis and Mare Tranquilitatis, Dokl. Akad. Nauk SSSR, 1971, vol.?201, pp. 957–960.
Yakovlev, O.I., Dikov, Yu.P., and Gerasimov, M.V., Experimental Study of Impact Vaporization of Ultramafic Substance, Geokhimiya, 1995, no. 8, pp. 1235-1248.
Ziegler, J.F., The Stopping and Range of Ions in Matter, vols.?2-6, New York: Pergamon, 1977-1985.
Ziegler, J.F., Biersack, J.P., and Littmark, U., The Stopping and Range of Ions in Solids, New York: Pergamon, 1996.
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Starukhina, L.V. Computer Simulation of Sputtering of Lunar Regolith by Solar Wind Protons: Contribution to Change of Surface Composition and to Hydrogen Flux at the Lunar Poles. Solar System Research 37, 36–50 (2003). https://doi.org/10.1023/A:1022347821862
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DOI: https://doi.org/10.1023/A:1022347821862