Advertisement

Astronomy Reports

, Volume 49, Issue 11, pp 916–931 | Cite as

Hard X-ray and gamma-ray flares on the Sun: Stereoscopic effects near the limb from observations on the 2001 Mars Odyssey spacecraft and near-Earth spacecraft

  • M. A. Livshits
  • V. A. Chernetskii
  • I. G. Mitrofanov
  • A. S. Kozyrev
  • M. L. Litvak
  • A. B. Sanin
  • V. I. Tret’yakov
  • W. Boynton
  • K. Shinohara
  • D. Hamara
Article

Abstract

We present the first results of data on solar flares detected by the HEND instrument onboard the 2001 Mars Odyssey interplanetary spacecraft during its flight to Mars and in orbit around Mars. The instruments carried by the spacecraft, which was developed at the Space Research Institute of the Russian Academy of Sciences, included a scintillation detector with two crystals, enabling the detection of photons with energies from tens of keV to 2.5 MeV with high time resolution. Several dozen flares were detected on both the sides visible from the Earth and back side of the Sun, supplementing other available data in a number of cases. A joint analysis of the HEND data together with data obtained in near-Earth orbits enabled the detection of variations in the integrated fluxes of photons with energies exceeding 80 keV during observations of flares near the limb from various directions. Two events were analyzed in great detail: the setting of a region displaying frequent very short flares on May 20, 2001, and the rising of the group 10486, which displayed numerous flare phenomena on the limb followed by extremely high activity in October–November 2003. These variations appear in simultaneous observations of limb M flares made at angles differing by only 8°–10°. Analyses of observations of rising sources obtained on two spacecraft lead to similar results. This indicates that the vast majority of emission at energies exceeding 80 keV arises at altitudes of no higher than seven to ten thousand kilometers. We briefly consider the powerful solar-disk gamma-ray flare of August 25, 2001. In this case, there are some differences in the behavior of the hard radiation in the decay phase for observations made at angles differing by 25°, which is most likely due to differences in the instrumental responses to radiation with this spectrum. The absence of hard radiation at great heights in the region of the “cusp” places some constraints on our picture of the physical processes occurring in powerful solar flares.

Keywords

Flare Solar Flare Scintillation Detector Instrumental Response Decay Phase 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    H. Hudson and J. Ryan, Annu. Rev. Astron. Astrophys. 33, 239 (1995).CrossRefADSGoogle Scholar
  2. 2.
    G. Rank, J. Ryan, H. Debrunner, et al., Astron. Astrophys. 378, 1046 (2001).CrossRefADSGoogle Scholar
  3. 3.
    M. A. Livshits and A. V. Belov, Astron. Zh. 81, 732 (2004) [Astron. Rep. 48, 665 (2004)].Google Scholar
  4. 4.
    S. R. Kane, Sol. Phys. 86, 355 (1983).ADSGoogle Scholar
  5. 5.
    S. Masuda, PhD Thesis (Univ. of Tokyo, Tokyo, 1994).Google Scholar
  6. 6.
    S. Masuda, T. Kosugi, H. Hara, et al., Nature 371, 495 (1994).CrossRefADSGoogle Scholar
  7. 7.
    E. Rieger, Sol. Phys. 121, 323 (1989).CrossRefADSGoogle Scholar
  8. 8.
    S. V. Bogovalov, S. R. Kel’ner, and Yu. D. Kotov, Astron. Zh. 65, 1275 (1988) [Sov. Astron. 32, 664 (1988)].ADSGoogle Scholar
  9. 9.
    P. Li, K. C. Hurley, C. R. Barat Talon, and Victoria Kurt, Astrophys. J. 426, 758 (1994).CrossRefADSGoogle Scholar
  10. 10.
    H. T. Gallagher, B. R. Dennis, S. Krucker, et al., Sol. Phys. 210, 341 (2002).CrossRefADSGoogle Scholar
  11. 11.
    W. V. Boynton, W. C. Feldman, I. G. Mitrofanov, et al., Space Sci. Rev. 110, 37 (2004).CrossRefADSGoogle Scholar
  12. 12.
    A. V. Belov, E. Garcia, V. G. Kurt, and E. Mavromichalaki, Kosm. Issled. (2005) (in press).Google Scholar
  13. 13.
    M. A. Livshits, V. A. Chernetskii, A. V. Bogovalov, et al., Astron. Vestn., No. 6 (2005) (in press).Google Scholar
  14. 14.
    S. N. Kuznetsov, K. Kudela, I. N. Myagkova, and B. Yu. Yushkov, in Proceedings of the 28th International Cosmic Ray Conference (Universal Academy Press, 2003), p. 3183.Google Scholar
  15. 15.
    O. V. Terekhov, Doctoral Dissertation (Institute for Space Research, Russian Academy of Sciences, Moscow, 1996).Google Scholar
  16. 16.
    I. M. Chertok and V. V. Grechnev, Astron. Zh. 80, 1013 (2003) [Astron. Rep. 47, 934 (2003)].Google Scholar
  17. 17.
    S. Krucker, in Proceedings of the 13th Cool Stars Cambridge Workshop, Hamburg (2004), ESA SP-560, p. 101.Google Scholar

Copyright information

© Pleiades Publishing, Inc. 2005

Authors and Affiliations

  • M. A. Livshits
    • 1
  • V. A. Chernetskii
    • 1
  • I. G. Mitrofanov
    • 2
  • A. S. Kozyrev
    • 2
  • M. L. Litvak
    • 2
  • A. B. Sanin
    • 2
  • V. I. Tret’yakov
    • 2
  • W. Boynton
    • 3
  • K. Shinohara
    • 3
  • D. Hamara
    • 3
  1. 1.Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave PropagationMoscowRussia
  2. 2.Space Research InstituteMoscowRussia
  3. 3.Arizona State UniversityArizonaUSA

Personalised recommendations