Advertisement

Solar Physics

, Volume 210, Issue 1–2, pp 229–243 | Cite as

Relative Timing and Spectra of Solar Flare Hard X-ray Sources

  • Säm Krucker
  • R.P. Lin
Article

Abstract

Hard X-ray lightcurves, spectrograms, images, and spectra of three medium-sized flares observed by the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) are presented. Imaging spectroscopy of the 20 February 2002, 11:06 UT flare at 10′′ spatial resolution, comparable to the best previous hard X-ray imaging from Yohkoh, shows two footpoints with an ∼ 8 s delay of peak emission between footpoints. Subsequent imaging at le4′′ shows three sources consistent with two separate loops and simultaneous brightening in connected footpoints. Imaging for the simple two footpoint flare of 2 June 2002 also shows simultaneous footpoint brightening. The more complex 17 March 2002 flare shows at least four different sources during the main peak of the event, and it is difficult to clearly demonstrate simultaneous brightening of connected footpoints. Non-thermal power laws are observed down to ∼ 12–13 keV without flattening in all these events, indicating the energy content in energetic electrons may be significantly greater than previously estimated from assumed 25 keV low energy cutoff. Simultaneously brightening footpoints show similar spectra, at least in the three flares investigated. Double-power-law spectra with a relatively sharp break are often observed.

Keywords

Thermal Emission Imaging Spectroscopy Impulsive Onset Overview Plot Spectrogram Plot 
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.

Supplementary material

5108115.zip (657 kb)
Supplementary material, approximately 660 KB.

References

  1. Alexander, D. and Metcalf, T. R.: 1997, Astrophys. J. 489, 442.CrossRefADSGoogle Scholar
  2. Alexander, D. and Metcalf, T. R.: 2002, Solar Phys., this volume.Google Scholar
  3. Aschwanden, M. J., Wills, M. J., Hudson, H. S., Kosugi, T., and Schwartz, R. A.: 1996, Astrophys. J. 468, 398.CrossRefADSGoogle Scholar
  4. Aschwanden, M. J. et al.: 2002, Solar Phys., this volume.Google Scholar
  5. Crosby, N. B., Aschwanden, M. J., and Dennis, B. R.: 1993, Solar Phys. 143, 275.CrossRefADSGoogle Scholar
  6. Delaboudinière J.-P. et al.: 1995, Solar Phys. 162, 291.CrossRefADSGoogle Scholar
  7. Sui, L., Holman, G. D., Dennis, B. R., Krucker, S., Schwartz, R. A., and Tolbert, K.: 2002, Solar Phys., this volume.Google Scholar
  8. Hurford, G. J. et al.: 2002, Solar Phys., this volume.Google Scholar
  9. Lin, R. P. et al.: 2002, Solar Phys., this volume.Google Scholar
  10. Krucker, S., Christe, S., Lin, R. P., Hurford, G. J., and Schwartz, R. A.: 2002, Solar Phys.,this volume.Google Scholar
  11. Masuda, S., Kosugi, T., Hara, H., Tsuneta, S., and Ogawara, Y.: 1994, Nature 371, 495.CrossRefADSGoogle Scholar
  12. Sakao, T., Kosugi, T., Masuda, S., Yaji, K., Inda-Koide, M., and Makishima, K.: 1994, Proceedings of Kofu Symposium, Kofu, Japan, p. 169.Google Scholar
  13. Sakao, T., Kosugi, T., Masuda, S., Yaji, K., Inda-Koide, M., and Makishima, K.: 1996, Adv. Space Res. 17, 60.CrossRefADSGoogle Scholar
  14. Vilmer, N. et al.: 2002, Solar Phys., this volume.Google Scholar

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Säm Krucker
    • 1
  • R.P. Lin
    • 1
    • 2
  1. 1.Space Sciences LabUniversity of CaliforniaBerkeleyU.S.A
  2. 2.Physics DepartmentUniversity of CaliforniaBerkeleyU.S.A

Personalised recommendations