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The Cosmic Ray Increases At 35 and 60 Kyr BP

Published online by Cambridge University Press:  18 July 2016

V Florinski ,
W I Axford  and
G P Zank
V Florinski*
Affiliation:
Institute of Geophysics and Planetary Physics, University of California, Riverside, California 92521, USA.
W I Axford*
Affiliation:
Institute of Geophysics and Planetary Physics, University of California, Riverside, California 92521, USA.
G P Zank*
Affiliation:
Institute of Geophysics and Planetary Physics, University of California, Riverside, California 92521, USA.
*
Corresponding author. Email: vflorins@citrus.ucr.edu.
Email: ian@axford.org.
Email: zank@ucrac1.ucr.edu.
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Abstract

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Concentrations of 10Be in ice cores and marine sediments exhibit 2 peaks with significant enhancements at 35,000 and 60,000 BP. This radioisotope is produced in the upper atmosphere by spallation of cosmic-ray protons and secondary neutrons on atmospheric nitrogen and oxygen. Previously suggested explanations for the increases include geomagnetic field reversals, a decrease in solar activity, and a supernova explosion. We propose an alternative explanation which involves a change in the galactic environment of the solar system. The structure of the heliosphere is investigated for a period when the Sun enters a cold, dense, unmagnetized interstellar cloud. Under these conditions, the heliosphere contracts to 25% its present size, significantly affecting galactic cosmic ray modulation and increasing anomalous cosmic ray fluxes. A tenfold increase in anomalous cosmic ray flux and a twofold increase in galactic cosmic ray intensity at Earth are possible in this high-density case if heliosheath modulation is reduced. We show that this increase in galactic cosmic ray intensity could be responsible for the peaks in 10Be records.

Type
Part II
Information
Radiocarbon , Volume 46 , Issue 2: Proceedings of the 18th International Radiocarbon Conference (Part 2 of 2), Conference Editors: Nancy Beavan Athfield, Rodger J Sparks , 2004 , pp. 683 - 690
Copyright
Copyright © The Arizona Board of Regents on behalf of the University of Arizona 

References

Axford, WI. 1981. Acceleration of cosmic rays by shock waves. Proceedings of the 17th International Cosmic Ray Conference (Paris) 12:155–204.Google Scholar
Baranov, VB, Malama, YG. 1993. Model of the solar wind interaction with the local interstellar medium: numerical solution of self-consistent problem. Journal of Geophysical Research 98:15,157–63.Google Scholar
Beer, J. 2000. Long-term indirect indices of solar variability. Space Science Reviews 94:53–66.Google Scholar
Beer, J, Blinov, A, Bonani, G, Finkel, RC, Hofmann, HJ, Lehmann, B, Oeschger, H, Sigg, A, Schwander, J, Staffelback, T, Stauffer, B, Suter, M, Wölfli, W. 1990. Use of 10Be in polar ice to trace the 11-year cycle of solar activity. Nature 347:164–6.Google Scholar
Brown, L, Stensland, GJ, Klein, J, Middleton, R. 1989. Atmospheric deposition of 7Be and 10Be. Geochimica et Cosmochimica Acta 53:135–42.Google Scholar
Cini Castagnoli, G, Albrecht, A, Beer, J, Bonino, G, Shen, C, Callegari, E, Taricco, C, Dittrich-Hannen, B, Kubik, P, Suter, M, Zhu, GM. 1995. Evidence for enhanced 10Be deposition in Mediterranean sediments 35 kyr BP. Geophysical Research Letters 22:707–10.Google Scholar
Cini Castagnoli, G, Bonino, G, Taricco, C, Lehman, B. 1998. Cosmogenic isotopes and geomagnetic signals in a Mediterranean sea sediment at 35,000 yr BP. Il Nuovo Cimento 21:243–6.Google Scholar
Cummings, AC, Stone, EC, Steenberg, CD. 2002. Composition of anomalous cosmic rays and other heliospheric ions. Astrophysical Journal 578:194–210.Google Scholar
Ellis, J, Fields, BD, Schramm, DN. 1996. Geological isotope anomalies as signatures of nearby supernovae. Astrophysical Journal 470:1227–36.Google Scholar
Fahr, HJ, Kausch, T, Scherer, H. 2000. A 5-fluid hydrodynamic approach to model the solar system—interstellar medium interaction. Astronomy and Astrophysics 357:268–82.Google Scholar
Fichtner, H. 2001. Anomalous cosmic rays: messengers from the outer heliosphere. Space Science Reviews 95: 639–754.Google Scholar
Florinski, V, Zank, GP, Pogorelov, NV. 2003. Galactic cosmic ray transport in the global heliosphere. Journal of Geophysical Research 108:1228.Google Scholar
Frisch, PC. 2000. The galactic environment of the Sun. Journal of Geophysical Research 105:10,279–89.Google Scholar
Graham, I, Ditchburn, R, Barry, B. 2003. Atmospheric deposition of 7Be and 10Be in New Zealand rain (1996–98). Geochimica et Cosmochimica Acta 67: 361–73.Google Scholar
Jokipii, JR, Kota, J, Merenyi, E. 1993. The gradient of galactic cosmic rays at the solar-wind termination shock. Astrophysical Journal 405:782–6.Google Scholar
Kocharov, GE. 1994. On the origin of cosmic rays. Astrophysical Letters and Communications 29:227–32.Google Scholar
Laj, C, Kissel, C, Scao, V, Beer, J, Thomas, DM, Guillou, H, Muscheler, R, Wagner, G. 2002. Geomagnetic intensity and inclination variations at Hawaii for the past 98 kyr from core SOH-4 (Big Island): a new study and a comparison with existing contemporary data. Physics of the Earth and Planetary Interiors 129:205–43.Google Scholar
Lallement, R. 2001. Heliopause and asteropauses. Astrophysics and Space Science 277:205–17.Google Scholar
Lauroesch, JT, Meyer, DM. 1999. Observations of small-scale interstellar structure in dense atomic gas. Astrophysical Journal 519:L181–L184.Google Scholar
Masarik, J, Beer, J. 1999. Simulation of particle fluxes and cosmogenic nuclide production in the earth's atmosphere. Journal of Geophysical Research 104:12,099–111.Google Scholar
McDonald, FB. 1998. Cosmic-ray modulation in the heliosphere—a phenomenological study. Space Science Reviews 83:33–50.Google Scholar
McHargue, LR, Damon, PE, Donahue, DJ. 1995. Enhanced cosmic-ray production of 10Be coincident with Mono Lake and Laschamp geomagnetic excursions. Geophysical Research Letters 22:659–722.Google Scholar
McHargue, LR, Donahue, DJ, Damon, PE, Sonett, CP, Biddulph, D, Burr, G. 2000. Geomagnetic modulation of the late Pleistocene cosmic-ray flux as determined by 10Be from Blake Outer Ridge marine sediments. Nuclear Instruments and Methods in Physics Research Section B 172:555–61.Google Scholar
Pauls, HL, Zank, GP, Williams, LL. 1995. Interaction of the solar wind with the local interstellar medium. Journal of Geophysical Research 100:21,595–604.Google Scholar
Raisbeck, GM, Yiou, F, Bourles, D, Lorius, C, Jouzel, J, Barkov, NI. 1987. Evidence for two intervals of enhanced 10Be deposition in Antarctic ice during the last glacial period. Nature 326:273–7.Google Scholar
Ramadurai, S. 1995. Very long time variations of the cosmic ray intensity and their origin. Advances in Space Research 15(1):41–8.Google Scholar
Robinson, C, Raisbeck, GM, Yiou, F, Lehman, B, Laj, C. 1995. The relationship between 10Be and geomagnetic field strength records in central North Atlantic sediments during the last 80 ka. Earth and Planetary Science Letters 136:551–7.Google Scholar
Scherer, K, Fichtner, H, Stawicki, O. 2002. Shielded by the wind: the influence of the interstellar medium on the environment of Earth. Journal of Atmospheric and Solar-Terrestrial Physics 64:795–804.Google Scholar
Smith, RK, Cox, DP. 2001. Multiple supernova remnant models of the Local Bubble and the soft X-ray background. Astrophysical Journal Supplement Series 134:283–309.Google Scholar
Sonett, CP, Morfill, GE, Jokipii, JR. 1987. Interstellar shock waves and 10Be from ice cores. Nature 330: 458–60.Google Scholar
Steenberg, CD, Moraal, H. 1996. An acceleration/modulation model for anomalous cosmic ray hydrogen in the heliosphere. Astrophysical Journal 463:776–83.Google Scholar
Steig, EJ, Polissar, PJ, Stuiver, M, Grootes, PM, Finkel, RC. 1996. Large amplitude solar modulation cycles of 10Be in Antarctica: implications for atmospheric mixing processes and interpretation of the ice core record. Geophysical Research Letters 23:523–6.Google Scholar
Wagner, G, Masarik, J, Beer, J, Baumgartner, S, Imboden, D, Kubik, PW, Synal, H-A, Suter, M. 2000. Reconstruction of the geomagnetic field between 20 and 60 kyr BP from cosmogenic radionuclides in the GRIP ice core. Nuclear Instruments and Methods in Physics Research B 172:597–604.Google Scholar
Zank, GP. 1999. Interaction of the solar wind with the local interstellar medium: a theoretical perspective. Space Science Reviews 89:413–688.Google Scholar
Zank, GP, Frisch, PC. 1999. Consequences of a change in the galactic environment of the Sun. Astrophysical Journal 518:965–73.Google Scholar
Zank, GP, Matthaeus, WH, Bieber, JW, Moraal, H. 1998. The radial and latitudinal dependence of the cosmic ray diffusion in the heliosphere. Journal of Geophysical Research 103:2085–97.Google Scholar
Zank, GP, Pauls, HL, Williams, LL, Hall, DT. 1996. Interaction of the solar wind with the local interstellar medium: a multifluid approach. Journal of Geophysical Research 101:21,639–55.Google Scholar