Geomagnetism and Aeronomy

, Volume 58, Issue 8, pp 1050–1056 | Cite as

Energy Spectra and Time Delays of Hard X-Rays of Solar Flares in Konus-Wind and RHESSI Experiments

  • Yu. E. CharikovEmail author
  • A. N. Shabalin
  • E. P. Ovchinnikova
  • A. L. Lysenko
  • S. A. Kuznetsov


This paper analyzes hard X-ray radiation of solar flares detected by Konus-Wind and RHESSI spacecrafts. X-ray quanta are measured using high energy, time (Konus-Wind), and spatial (RHESSI) resolution. Spectra of accelerated electrons are calculated from the spectra of hard X-rays both via the forward-fitting method and the Tikhonov reconstruction method. The X-ray data for the solar flare of July 8, 2013, 0120:24 UT are analyzed. In Konus-Wind data the irregularities and inversions are detected in the energy spectrum. According to RHESSI data, the hard X-ray (HXR) energy spectrum is smoother, although it contains breaks. The X-ray energy spectrum determined by the forward-fitting method is hard at the peak of the flux, and the spectrum index is γ ≈ 3.5. Over time, the HXR spectrum is significantly softened, and the spectrum index increases to γ ≈ 7.5. X-ray time delays are determined by a correlation analysis of the time series of different energies. The time delay spectrum is U-shaped with a 47-keV break in the energy for the Konus-Wind data and 57 keV for the RHESSI data.



The work of Charikov, Shabalin, Lysenko, and Ovchinnikova was supported by the Russian Science Foundation, project no. 17-12-01378. The work of Kuznetsov (the synthesis of radio data from the observations on the Nobeyama radioheliograph) was partially supported by the Russian Science Foundation, project no. 16-12-10448.


  1. 1.
    Aptekar, R.F., Frederiks, D.D., Golenetskii, S.V., et al., Konus-W gamma-ray burst experiment for the GGS Wind spacecraft, Space Sci. Rev., 1995, vol. 71, nos. 1–4, pp. 265–272.CrossRefGoogle Scholar
  2. 2.
    Aschwanden, M.J., Schwartz, R.A., and Alt, D.M., Electron time-of-flight differences in solar flares, Astrophys. J., 1995, vol. 447, pp. 923–935.CrossRefGoogle Scholar
  3. 3.
    Ashwanden, V.J., Bynum, R.V., Kosugi, T., Hudson, H.S., and Schwartz, R.A., Electron trapping times and trap densities in solar flare loops measured with COMPTON and YOHKOH, Astrophys. J., 1997, vol. 487, no. 2, pp. 936–955.CrossRefGoogle Scholar
  4. 4.
    Brown, J.C., The deduction of energy spectra of non-thermal electrons in flares from the observed dynamic spectra of hard X-ray bursts, Sol. Phys., 1971, vol. 18, no. 3, pp. 489–502.CrossRefGoogle Scholar
  5. 5.
    Brown, J.C., Emslie, A.G., Holman, G.D., Johns, KrullC.M., Kontar, E.P., Lin, R.P., Massone, A.M., and Piana, M., Evaluation of algorithms for reconstructing electron spectra from their bremsstrahlung hard X-ray spectra, Astrophys. J., 2006, vol. 643, no. 1, pp. 523–531.CrossRefGoogle Scholar
  6. 6.
    Charikov, Y.E. and Shabalin, A.N., Influence of magnetic turbulence on the propagation of accelerated electrons and hard X-ray brightness distribution in solar flares, Geomagn. Aeron. (Engl. Transl.), 2015, vol. 55, no. 8, pp. 1104–1111.Google Scholar
  7. 7.
    Charikov, Yu.E. and Shabalin, A.N., Hard X-ray generation in the turbulent plasma of solar flares, Geomagn. Aeron. (Engl. Transl.), 2016, vol. 56, no. 8, pp. 1068–1074.Google Scholar
  8. 8.
    Charikov, Yu.E., Globina, V.I., and Sklyarova, E.M., Spectra of time delays in hard X-ray radiation of solar flares according to BATSE spectrometer data, Nauchno-Tekh. Vedomosti S.-Peterb. Gos. Politekh. Univ., Ser. Fiz.–Mat. Nauki, 2013, vol. 177, pp. 237–244.Google Scholar
  9. 9.
    Charikov, Yu.E., Globina, V.I., Shabalin, A.N., and Elfimova, E.P., Localization of electron acceleration in solar flares based on the spectrum analysis of hard X-ray time delays, Geomagn. Aeron. (Engl. Transl.), 2015, vol. 55, no. 7, pp. 1000–1007. Google Scholar
  10. 10. Scholar
  11. 11.
    Kosugi, T., Makishima, K., Murakami, T., Sakao, T., Dotani, T., Inda, M., Kai, K., Masuda, S., Nakajima, H., Ogawara, Y., Sawa, M., and Shibasaki, K., The Hard X-ray Telescope (HXT) for the SOLAR-A Mission, in The Yohkoh (Solar-A) Mission, Dordrecht: Springer, 1991, pp. 17–36.Google Scholar
  12. 12.
    Lemen, J.R., Title, A.M., Akin, C., et al., The atmospheric imaging assembly (AIA) on the solar dynamics observatory (SDO), Sol. Phys., 2012, vol. 275, nos. 1–2, pp. 17–40.CrossRefGoogle Scholar
  13. 13.
    Lin, R.P., Dennis, B.R., Hurford, G.J., et al., The Reuven Ramaty high-energy solar spectroscopic imager (RHESSI), Sol. Phys., 2002, vol. 210, nos. 1–2, pp. 3–32.CrossRefGoogle Scholar
  14. 14.
    Nakajima, H., Nishio, M., Enome, S., et al., The Nobeyama radioheliograph, Proc. IEEE, 1994, vol. 82, no. 5, pp. 705–713.CrossRefGoogle Scholar
  15. 15.
    Reznikova, V.E., Melnikov, V.F., Shibasaki, K., Gorbikov, S.P., Pyatakov, N.P., Myagkova, I.N., and Ji, H., 2002 August 24 limb flare loop: Dynamics of microwave brightness distribution, Astrophys. J., 2009, vol. 697, no. 1, pp. 735–746.CrossRefGoogle Scholar
  16. 16.
    Schou, P.H. and Scherrer, R.I., Bush Design and ground calibration of the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO), Sol. Phys., 2012, vol. 275, nos. 1–2, pp. 229–259.CrossRefGoogle Scholar
  17. 17.
    Tikhonov, A.N. and Arsenin, V.Ya., Metody resheniya nekorrektnykh zadach (Methods for Solving Incorrectly Posed Problems), Moscow: Nauka, 1979.Google Scholar
  18. 18.
    Verlan’, A.F. and Sizikov, V.S., Metody resheniya integral’nykh uravnenii s programmami dlya EVM (Methods for Solving Integral Equations with Computer Programs), Kiev: Naukova dumka, 1978.Google Scholar
  19. 19.
    Zharkova, V.V., Brown, J.C., and Syniavskii, D.V., Electron beam dynamics and hard X-ray bremsstrahlung polarization in a flaring loop with return current and converging magnetic field, Astron. Astrophys., 1995, vol. 304, pp. 284–295.Google Scholar

Copyright information

© Pleiades Publishing, Ltd. 2018

Authors and Affiliations

  • Yu. E. Charikov
    • 1
    Email author
  • A. N. Shabalin
    • 1
  • E. P. Ovchinnikova
    • 1
  • A. L. Lysenko
    • 1
  • S. A. Kuznetsov
    • 2
  1. 1.Ioffe Institute, Russian Academy of SciencesSt. PetersburgRussia
  2. 2.The Central Astronomical Observatory, Russian Academy of SciencesSt. PetersburgRussia

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