Abstract
Relative abundances of energetic nuclei in the 4 July 1974 solar event are presented. The results show a marked enhancement of abundances that systematically increase with nuclear charge numbers in the range of the observation, 6 ≤ Z ≤ 26 for energies above 15 MeV nucl.−1 While such enhancements are commonly seen below 10 MeV nucl−1, most observations at higher energies are found to be consistent with solar system abundances. The energy spectrum of oxygen is observed to be significantly steeper than most other solar events studied in this energy region. It is proposed that these observations are characteristic of particle populations at energies ∼1 MeV nucl−1, and that the anomalous features observed here may be the result of the high energy extension of such a population that is commonly masked by other processes or populations that might occur in larger solar events.
Similar content being viewed by others
References
Armstrong, T. P. and Krimigis, S. M.: 1971, J. Geophys. Res. 76, 4230.
Armstrong, T. P. and Krimigis, S. M.: 1975, 14th International Cosmic Ray Conference, Conference Papers 5, 1592.
Armstrong, T. P., Krimigis, S. M., Hovestadt, D., Klecker, B., and Gloeckler, G.: 1977, to be published in Solar Phys.
Bertsch, D. L. Biswas, S., and Reames, D. V.: 1974, Solar Phys. 39, 479.
Bertsch, D. L., Fichtel, C. E., and Reames, D. V.: 1972, Astrophys. J. 171, 169.
Bertsch, D. L., Biswas, S., Fichtel, C. E., Pellerin, C. J., and Reames, D. V.: 1973a, Astrophys. J. 180, 583.
Bertsch, D. L., Biswas, S., Fichtel, C. E., Pellerin, C. J., and Reames, D. V.: 1973b, Solar Phys. 31, 247.
Biswas, S., Fichtel, C. E., and Guss, D. E.: 1962, Phys. Rev. 128, 2756.
Cameron, A. G. W.: 1973, Space Sci. Rev. 15, 121.
Crawford, H. C., Price, P. B., and Sullivan, J. D.: 1972, Astrophys. J. 175, L149.
Crawford, H. C., Price, P. B., Cartwright, B. G., and Sullivan, J. D.: 1975, Astrophys. J. 195, 213.
Durgaprasad, N., Fichtel, C. E., Guss, D. E., and Reames, D. V.: 1968, Astrophys. J. 154, 307.
Fan, C. Y., Gloeckler, G., and Hovestadt, D.: 1975, in S. R. Kane (ed.), ‘Solar Gamma-, X-, and EUV Radiation’, IAU Symp. 60, 411.
Gloeckler, G., Hovestadt, D., Vollmer, O., and Fan, C. Y.: 1975, Astrophys. J. 200, L45.
Hovestadt, D., Vollmer, O., Gloeckler, G., and Fan, C. Y.: 1973, 13th International Cosmic Ray Conference, Conference Papers 2, 1498.
Mogro-Campero, A. and Simpson, J. A.: 1972a, Astrophys. J. 171, L5.
Mogro-Campero, A. and Simpson, J. A.: 1972b, Astrophys. J. 177, L37.
Pellerin, C. J.: 1974, Ph.D. Thesis, Catholic University of America.
Pellerin, C. J.: 1975, Solar Phys. 41, 449.
Roelof, E. C. and Krimigis, S. M.: 1973, J. Geophys. Res. 78, 5375.
Smart, D. F. and Shea, M. A.: 1972, J. Geophys. Res. 77, 4595.
Teegarden, B. J. von Rosenvinge, T. T., and McDonald, F. B.: 1973, Astrophys. J. 180, 571.
Withbroe, G. L.: 1971, in K. B. Gebbie (ed.), ‘The Menzel Symposium on Solar Physics, Atomic Spectra and Gaseous Nebula’, NBS Spec. Publ. 353, 127.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bertsch, D.L., Reames, D.V. Enhancement of solar heavy nuclei at high energies in the 4 July 1974 event. Sol Phys 55, 491–497 (1977). https://doi.org/10.1007/BF00152589
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00152589