Advertisement

Solar Physics

, Volume 113, Issue 1–2, pp 35–48 | Cite as

Impulsive and hot thermal solar flares

  • Saku Tsuneta
Article

Abstract

Some X-class flares (hot thermal flares, HTF) observed with the Hinotori satellite show unique behavior: slow time variability, a compact hard X-ray source containing dense (n > 1011 cm−3) and hot (T > 3 × 107 K) plasma, and unusually weak microwave emission in spite of the intense magnetic field (B > 330 G) required theoretically to sustain the hot plasma. These observations show that HTF's have essentially thermal characteristics throughout the flare evolution, while in impulsive flares, there is a transition in the energy release mode from particle acceleration (impulsive phase) to plasma heating (gradual phase). This behavior can be explained in a unified manner by employing parallel DC electric field acting over large distances.

Keywords

Flare Solar Flare Release Mode Plasma Heating Impulsive Phase 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Bai, T., and Dennis, B. R.: 1985, Astrophys. J. 287, 179.Google Scholar
  2. Dennis, B. R.: 1985, Solar Phys. 100, 465.ADSCrossRefGoogle Scholar
  3. De Jager, C.: 1986, Space Sci. Rev. 44, 43.ADSCrossRefGoogle Scholar
  4. Duijveman, A., Hoyng, P., and Machado, M. E.: 1983, Solar Phys. 81, 137.ADSCrossRefGoogle Scholar
  5. Kai, K.: 1985a, Publ. Astron. Soc. Japan 37, 155.ADSGoogle Scholar
  6. Kai, K.: 1985b, Proc. Cosmic Radiation Symposium (ISAS, Tokyo), p 69.Google Scholar
  7. Kawabata, K. Ogawa, H. and Suzuki, I.:1983, Solar Phys. 86, 247.ADSCrossRefGoogle Scholar
  8. Kondo, I.: 1982, in Y. Tanaka et al. (eds.) Proc. Hinotori Symposium on Solar Flares (ISAS, Tokyo), p. 3.Google Scholar
  9. Kundu, M and Woodgate, B (eds.): 1986, Energetic Phenomena on the Sun (NASA CP-2439), p. 2–19.Google Scholar
  10. Lemmens, A. and De Jager, C.: 1986, Solar Phys. 106, 365.ADSCrossRefGoogle Scholar
  11. Lin, R. P., Schwartz, R. A., Pelling, R. M., and Hurley, K.C.: 1981, Astrophys. J. (Letts.) 251, L109.ADSCrossRefGoogle Scholar
  12. Lin, R. P., Schwartz, R. A.: 1987, Astrophys. J. 312, 462.ADSCrossRefGoogle Scholar
  13. Machado, M. E., Duijveman, A., and Dennis, B. R.: 1982, Solar Phys. 79, 85.ADSCrossRefGoogle Scholar
  14. Ogawara, Y: 1988, in these proceedings.Google Scholar
  15. Sakurai, T.: 1983, Solar Phys. 86, 339.ADSCrossRefGoogle Scholar
  16. Strong, K. T.: 1984, Solar Phys. 91, 325.ADSCrossRefGoogle Scholar
  17. Tanaka, K., Watanabe, T., Nishi, K., and Akita, K.: 1982, Astrophys. J. (Letts.) 254, L59.ADSCrossRefGoogle Scholar
  18. Tanaka, Y.: 1983, Solar Phys. 86, 3.ADSCrossRefGoogle Scholar
  19. Tsuneta, S: 1984, in J.-C. Pecker and Y. Uchida (eds.) Proc. Japan-France Seminar on Active Phenomena in the Outer Atmospheres of Stars and the Sun, Paris p. 243.Google Scholar
  20. Tsuneta, S. et. al.: 1984a, Astrophys. J. 280, 887.ADSCrossRefGoogle Scholar
  21. Tsuneta, S. et. al.: 1984b, Astrophys. J. 284, 827.ADSCrossRefGoogle Scholar
  22. Tsuneta, S.: 1985, Astrophys. J. 290, 353.ADSCrossRefGoogle Scholar

Copyright information

© D. Reidel Publishing Company 1987

Authors and Affiliations

  • Saku Tsuneta
    • 1
  1. 1.Division of SpectroscopyTokyo Astronomical Observatory University of TokyoTokyoJapan

Personalised recommendations