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Solar gamma rays

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Abstract

The theory of gamma-ray production in solar flares is treated in detail. Both lines and continuum are produced. The strongest line predicted at 2.225 MeV with a width of less than 100 eV and detected at 2.24±0.02 MeV, is due to neutron capture by protons in the photosphere. Its intensity is dependent on the photospheric 3He abundance. The neutrons are produced in nuclear reactions of flare accelerated particles which also produce positrons and prompt nuclear deexcitation lines. The strongest prompt lines are at 4.43 MeV from 12C and at ∼6.2 from 16O and 15N. These lines result from both direct excitation and spallation. The widths of individual prompt lines are determined by nuclear kinematics. The width of the 4.43 MeV line is ∼100 keV and that of the 6.2 MeV feature is ∼300 keV. Both these lines have been observed from a solar flare. Other potentially observable lines are predicted at 0.845 and 1.24 MeV from 56Fe, at 1.63 MeV principally from 14N and 20Ne, at 1.78 MeV from 28Si, at ∼5.3 MeV from 15O and 15N, and at 7.12 MeV from 16O. The widths of the iron lines are only a few keV, while those of the other lines are about 100 keV. The only other observed line is at 0.511 MeV from positron annihilation. The width of this line is determined by the temperature, and its temporal variation depends on the density of the ambient medium in the annihilation region. Positrons can also annihilate from the 3 S state of positronium to produce a 3-photon continuum below 0.511 MeV. In addition, the lines of 7Li and 7Be at 0.478 keV and 0.431 keV, which have kinematical widths of ∼30 keV, blend into a strong feature just below the 0.511 MeV line.

From the comparison of the observed and calculated intensities of the line at 4.4 MeV to that of the 2.2 MeV line it is possible to obtain information on the spectrum of accelerated nuclei in flares. Moreover, from the absolute intensities of these lines the total number of accelerated nuclei at the Sun and their heating of the flare region can be estimated. We find that about 1033 protons of energies greater than 30 MeV were produced in the 1972, August 4 flare.

The gamma-ray continuum, produced by electron bremsstrahlung, allows the determination of the spectrum and number of accelerated electrons in the MeV region. From the comparison of the line and continuum intensities we find a proton-to-electron ratio of about 10 to 102 at the same energy for the 1972, August 4 flare. For the same flare the protons above 2.5 MeV which are responsible for the gamma-ray emission produce a few percent of the heat generated by the electrons which make the hard X-rays above 20 keV.

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References

  • Akhiezer, A. I. and Berestetskii, V. B.: 1965, Quantum Electrodynamics, Interscience Publishers, New York.

    Google Scholar 

  • Albouy, M. G., Cohen, J. P., Gusakow, M., Poffe, N., Serbolle, H., and Valentin, L.: 1962, Phys. Letters 2, 306.

    Google Scholar 

  • Ascuito, R. J.: 1972, Nuclear Phys. 192, 97.

    Google Scholar 

  • Ashery, D.: 1969, Nuclear Phys. A136, 481.

    Google Scholar 

  • Audouze, J., Ephere, M., and Reeves, H.: 1967, in B. S. P. Shen (ed.), High Energy Nuclear Reactions in Astrophysics, W. A. Benjamin, New York, p. 255.

    Google Scholar 

  • Bair, J. K.: 1973, Phys. Rev. C8, 120.

    Google Scholar 

  • Bair, J. K. and Haas, F. X.: 1973, Phys. Rev. C7, 1356.

    Google Scholar 

  • Bair, J. K. and Willard, H. B.: 1962, Phys. Rev. 128, 299.

    Google Scholar 

  • Barkas, W. H. and Berger, M. J.: 1964, Tables of Energy Losses and Ranges of Heavy Charged Particles., NASA SP-3013 (National Aeronautics and Space Administration, Washington, D. C.).

    Google Scholar 

  • Berger, M. J. and Seltzer, S. M.: 1964, Tables of Energy Losses and Ranges of Electrons and Positrons, NASA SP-3012 (National Aeronautics and Space Administration, Washington, D.C.).

    Google Scholar 

  • Bergman, C. and Hobbie, R. K.: 1971, Phys. Rev. C3, 1729.

    Google Scholar 

  • Biermann, L., Haxel, O., and Schluter, A.: 1951, Z. Naturforsch. 6a, 47.

    Google Scholar 

  • Bland, C. J.: 1966, Nuovo Cimenta 44B, 427.

    Google Scholar 

  • Blatchley, D. E. and Bent, R. D.: 1965, Nuclear Phys. 61, 641.

    Google Scholar 

  • Blatt, J. M. and Weisskopf, V. F.: 1952, Theoretical Nuclear Physics, John Wiley & Sons, New York.

    Google Scholar 

  • Boldt, E. A. and Serlemitsos, P. J.: 1969, Astrophys. J. 157, 557.

    Google Scholar 

  • Brown, J. C.: 1973, Solar Phys. 31, 143.

    Google Scholar 

  • Cameron, A. G. W.: 1973, Space Sci. Rev. 15, 121.

    Google Scholar 

  • Cheng, C. C.: 1972, Space Sci. Rev. 13, 3.

    Google Scholar 

  • Chupp, E. L.: 1964, AAS-NASA Symposium on the Physics of Solar Flares, NASA SP-50 (National Aeronautics and Space Administration, Washington, D.C., p. 445.

    Google Scholar 

  • Chupp, E. L., Forrest, D. J., Higbie, P. R., Suri, A. N., Tsai, C., and Dunphy, P. P.: 1973, Nature 241, 333.

    Google Scholar 

  • Chupp, E. L., Forrest, D.J., and Suri, A. N.: 1975, in S. Kane (ed.), ‘Solar γ, X and EUV Radiations’, IAU Symp. 68, to be published.

  • Clegg, A. B., Foley, K. J., Salmon, G. L., and Segel, R. E.: 1961, Proc. Phys. Soc. 78, 681.

    Google Scholar 

  • Correlli, J. C., Bleuler, E., and Tendam, D. J.: 1959, Phys. Rev. 116, 1184.

    Google Scholar 

  • Dere, K. P., Horan, D. M., and Kreplin, R. W.: 1973, in H. E. Coffey (ed.), World Data Center Rept. UAG-28 part II, Collected Data Reports on August 1972 Solar Terrestrial Events, p. 298.

  • Dolan, J. F. and Fazio, G. G.: 1965, Rev. Geophys. 3, 319.

    Google Scholar 

  • Dubov, E. E.: 1963, Izv. Krymsk. Astrofiz. Obs. 29, 86.

    Google Scholar 

  • Fawzi, M. A.: 1972, Z. Physik 250, 120.

    Google Scholar 

  • Foley, K. J., Salmon, G. L. and Clegg, A. B.: 1962, Nuclear Phys. 31, 43.

    Google Scholar 

  • Frost, K. J.: 1969. Astrophys. J. Letters 158, L159.

    Google Scholar 

  • Furukawa, M. and Tanaka, S.: 1961, J. Phys. Soc. Japan 16, 129.

    Google Scholar 

  • Gibbons, J. H. and Macklin, R. L.: 1959, Phys. Rev. 114, 571.

    Google Scholar 

  • Giovanelli, R. G.: 1946, Nature 158, 81.

    Google Scholar 

  • Gordon, I. M.: 1954, Doklak. Akad. Nauk SSSR 94, 813.

    Google Scholar 

  • Gruber, D. E., Peterson, L. E., and Vette, J. I.: 1973, in R. Ramaty and R. G. Stone (eds.), High Energy Phenomena on the Sun, NASA SP-342, National Aeronautics and Space Administration, Washington, D.C., p. 147.

    Google Scholar 

  • Haas, F. X. and Bair, J. K.: 1973, Phys. Rev. C. 7, 2432.

    Google Scholar 

  • Harvey, B. G., Rivet, E. J., Springer, H., Meriwether, J. R., Jones, W. B., Elliot, J. H., and Darriulat, P.: 1964, Nuclear Phys. 52, 465.

    Google Scholar 

  • Heitler, W.: 1954, The Quantum Theory of Radiation, Oxford University Press, London.

    Google Scholar 

  • Hess, W. N.: 1958, Rev. Mod. Phys. 39, 368.

    Google Scholar 

  • Hess, W. N.: 1962, 5th Interamerican Seminar on Cosmic Rays (La Paz Bolivia), p. 17.

  • Ito, K. and Okazoe, H.: 1969, Acha. Phys. Hung. 29, Suppl. 2, 679.

    Google Scholar 

  • Ito, K., Okazoe, H., and Yoshimori, M.: 1968, Can. J. Phys. 46, S780.

    Google Scholar 

  • Jacobs, W. W., Bodansky, D., Chamberlin, D., and Oberg, D. L.: 1974, Phys. Rev. C9, 2134.

    Google Scholar 

  • Koch, H. W. and Motz, J. W.: 1959, Rev. Mod. Phys. 31, 920.

    Google Scholar 

  • Kohl, J. W., Bostrom, C. O., and Williams, D. J.: 1973, in H. E. Coffey (ed.), World Data Center Rept. UAG-28 part II, Collected Data Reports on August 1972 Solar Terrestrial Events, p. 330.

  • Kozlovsky, B. and Ramaty, R.: 1974a, Astrophys. J. Letters 191, L43.

    Google Scholar 

  • Kozlovsky, B. and Ramaty, R.: 1974b, Astron. Astrophys. 34, 477.

    Google Scholar 

  • Kozlovsky, B. and Ramaty, R.: 1974c, Astron. Astrophys. 36, 307.

    Google Scholar 

  • Kuzhevskii, B. M.: 1968, Sov. Astron. 12, 595.

    Google Scholar 

  • Lapointe, S. M.: 1960, unpublished thesis, Cornell University.

  • Leventhal, M.: 1973, Astrophys. J. Letters 183, L147.

    Google Scholar 

  • Lingenfelter, R. E.: 1969, Solar Phys. 8, 341.

    Google Scholar 

  • Lingenfelter, R. E., Flamm, E. J., Canfield, E. H., and Kellman, S.: 1965a, J. Geophys. Res. 70, 4077.

    Google Scholar 

  • Lingenfelter, R. E., Flamm, E. J., Canfield, E. H., and Kellman, S.: 1965b, J. Geophys. Res. 70, 4087.

    Google Scholar 

  • Lingenfelter, R. E. and Ramaty, R.: 1967, in B. S. P. Shen (ed.), High Energy Nuclear Reactions Astrophysics, W. A. Benjamin, New York, p. 99.

    Google Scholar 

  • McGowan, F. K., Milner, W. Y., Kim, H. J., and Hyatt, W.: 1969, Nuclear Data Tables A6, 353.

    Google Scholar 

  • McGowan, F. K., Milner, W. Y., Kim, H. J., and Hyatt, W.: 1970, Nuclear Data Tables A8, 199.

    Google Scholar 

  • Meneguzzi, M., Audouze, J., and Reeves, H.: 1971, Astron. Astrophys. 15, 337.

    Google Scholar 

  • Meyer, J. P.: 1972, Astron. Astrophys. Suppl. 7, 417.

    Google Scholar 

  • Meyerhof, W. E. and Tombrello, T. A.: 1968, Nuclear Phys. A109, 1.

    Google Scholar 

  • Mitchel, G. E., Carter, E. B., and Davis, R. H.: 1964, Phys. Rev. 133, B1434.

    Google Scholar 

  • Mitler, H. E.: 1972, Astrophys. Space Sci. 17, 186.

    Google Scholar 

  • Morgan, J. F. and Hobbie, R. K.: 1970, Phys. Rev. C1, 155.

    Google Scholar 

  • Morrison, P.: 1958, Nuovo Cimento 7, 858.

    Google Scholar 

  • Najita, K. and Orrall, F. Q.: 1970, Solar Phys. 15, 176.

    Google Scholar 

  • Nelson, J. W., Carter, E. B., Mitchell, G. E., and Davis, R. H.: 1963, Phys. Rev. 129, 1723.

    Google Scholar 

  • Neupert, W. M.: 1968, Astrophys. J. Letters 153, L59.

    Google Scholar 

  • Oda, Y., Takeda, M., Takano, T., Yamazaki, T., Hu, C., Kikuchi, K., Kobayashi, S., Matsuda, K., and Nagahara, Y.: 1960, J. Phys. Soc. Japan 15, 760.

    Google Scholar 

  • Ramaty, R. and Lingenfelter, R. E.: 1969, Astrophys. J. 155, 587.

    Google Scholar 

  • Ramaty, R. and Lingenfelter, R. E.: 1973a, in R. Ramaty and R. G. Stone (eds.), High Energy Phenomena on the Sun, NASA SP-342 National Aeronautics and Space Administration, Washington, D.C., p. 301.

    Google Scholar 

  • Ramaty, R. and Lingenfelter, R. E.: 1973b, Conference Papers, 13th International Cosmic Ray Conference, University of Denver, Colorado, p. 1590.

    Google Scholar 

  • Ramaty, R. and Kozlovsky, B.: 1974, Astrophys. J. 193, 729.

    Google Scholar 

  • Ramaty, R. and Lingenfelter, R. E.: 1975a, in S. Kane (ed.), ‘Solar γ, X and EUV Radiations’, IAU Symp. 68, 363.

  • Ramaty, R. and Lingenfelter, R. E.: 1975b, Proc. of 6th Leningrad Symposium on Particle Acceleration and Nuclear Reactions in Space, to be published.

  • Reppin, C., Chupp, E. L., Forrest, D. J., and Suri, A. N.: 1973, Conference Papers, 13th International Cosmic Ray Conference, University of Denver, Denver, Colorado, p. 1577.

    Google Scholar 

  • Rimmer, E. M. and Fisher, P. S.: 1968, Nuclear Phys. A108, 561.

    Google Scholar 

  • Sekharan, K. K., Divatia, A. S., Mehta, M. K., Kerekatte, S. S., and Nambiar, K. B.: 1967, Phys. Rev. 156, 1187.

    Google Scholar 

  • Shklovsky, I. S.: 1965, Soviet Astron. AJ. 8, 538.

    Google Scholar 

  • Smith, S. M., Tibell, G., Cowley, A. A., Goldberg, D. A., Pugh, H. G, Reichart, W., and Wall, N. S.: 1973, Nuclear Phys. A207, 273.

    Google Scholar 

  • Somov, B. V. and Syrovatskii, S. I.: 1974, Solar Phys. 39, 415.

    Google Scholar 

  • Stecker, F. W.: 1969, Astrophys. Space Sci. 3, 479.

    Google Scholar 

  • Stecker, F. W.: 1970, Astrophys. Space Sci. 6, 377.

    Google Scholar 

  • Suri, A. N., Chupp, E. L., Forrest, D. J., and Reppin, C.: 1975, preprint.

  • Švestka, Z.: 1970, Solar Phys. 13, 471.

    Google Scholar 

  • Syrovatskii, S. I.: 1959, Soviet Astron. AJ. 3, 22.

    Google Scholar 

  • Syrovatskii, S. I. and Shmeleva, O. P.: 1972, Soviet Astron. AJ. 16, 273.

    Google Scholar 

  • Tanaka, S. and Furukawa, M.: 1959, J. Phys. Soc. Japan 14, 1269.

    Google Scholar 

  • van Beek, H. F., Hoyng, P., and Stevens, G. A.: 1973, in H. E. Coffey (ed.), World Data Center Rept. UAG-28 part II, Collected Data Reports on August 1972 Solar Terrestrial Events, p. 319.

  • Walton, R. B., Clement, J. D., and Boreli, F.: 1957, Phys. Rev. 107, 1065.

    Google Scholar 

  • Wang, H. T. and Ramaty, R.: 1974, Solar Phys. 36, 129.

    Google Scholar 

  • Wang, H. T.: 1975, Ph. D. Thesis, University of Maryland.

  • Webber, W. R., Roelof, E. C., McDonald, F. B., Teegarden, B. J., and Trainor, J.: 1975, Astrophys. J. (to be published).

  • Yavin, A. I. and Farwell, G. W.: 1959, Nuclear Phys. 12, 1.

    Google Scholar 

  • Zirin, H. and Tanaka, K.: 1973, Solar Phys. 32, 173.

    Google Scholar 

  • Zobel, W., Maienschein, F. C., and Scroggs, R. J.: 1965, in A. Reetz (ed.), Second Symposium on Protection Against Radiation in Space, NASA SP-71, National Aeronautics and Space Administration, Washington, D.C., p. 341.

    Google Scholar 

  • Zobel, W., Maienschein, F. C., Todd, J. H., and Chapman, G. T.: 1968, Nuclear Science and Engineering 32, 392.

    Google Scholar 

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Author notes

  1. B. Kozlovsky

    Present address: Physics Dept., Tel Aviv University, Israel

Authors and Affiliations

  1. Laboratory for High Energy Astrophysics, NASA-Goddard Space Flight Center, Greenbelt, Maryland, USA

    R. Ramaty & B. Kozlovsky

  2. Dept. of Astronomy and Dept. of Planetary and Space Science, University of California, Los Angeles, California, USA

    R. E. Lingenfelter

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  1. R. Ramaty
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  2. B. Kozlovsky
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NAS-NRC Resident Research Associate.

Research supported by the National Science Foundation under Grant GP 31620.

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Ramaty, R., Kozlovsky, B. & Lingenfelter, R.E. Solar gamma rays. Space Sci Rev 18, 341–388 (1975). https://doi.org/10.1007/BF00212911

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