Skip to main content
SpringerLink
Log in

Accumulation of accelerated electrons in coronal loops and time delays of solar flare nonthermal emission

  • Published:
Geomagnetism and Aeronomy Aims and scope Submit manuscript

Abstract

The mechanisms by which accelerated electrons accumulate in flare loops with regard to the observed time delays between peaks of prolonged (≫1 s) hard X-ray pulses with different energies are considered. The focus is on an analysis of electron pitch-angle scattering by background plasma particles and/or turbulent pulsations in extreme cases of frequent and rare collisions. It was shown that it is difficult to explain the origination of time delays in the scope of a diffusion model when the electron free path length (l) in the corona is smaller than the flare loop length (L). The accumulation of energetic particles in loops at l > L is related to a trap-plus-precipitation model in which the regime of weak pitch angle diffusion of trapped electrons in the loss cone predominates.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Aschwanden, M.J., Hudson, H., Kosugi, T., and Schwartz, R.A., Electron time-of-flight measurements during the Masuda Flare, 1992 January 13, Astrophys. J., 1996, vol. 464, no. 2, pp. 985–998.

    Article  Google Scholar 

  • Aschwanden, M.J., Bynum, R.M., 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.

    Article  Google Scholar 

  • Bespalov, P.A. and Trakhtengerts, V.Yu., Al’fvenovskie mazery (Alfvèn Masers), Gorky: IPFAN, 1986.

    Google Scholar 

  • Bespalov, P.A., Zaitsev, V.V., and Stepanov, A.V., Consequences of strong pitch-angle diffusion of particles in solar flares, Astrophys. J., 1991, vol. 374, pp. 369–373.

    Article  Google Scholar 

  • Earl, J.A., The diffusive idealization of charged-particle transport in random magnetic fields, Astrophys. J., 1974, vol. 193, no. 1, pp. 231–242.

    Article  Google Scholar 

  • Fletcher, L., Looptop Hard X-Ray Sources, in ESA SP-448, The 9th European Meeting on Solar Physics “Magnetic Fields and Solar Sources,” Noordwijk, 1999, pp. 693–700.

    Google Scholar 

  • Huang, J., Yan, Y., and Tsap, Yu., Energetic electron propagation in the decay phase of non-thermal flare emission, Astrophys. J., 2014, vol. 787, no. 2, p. 123.8.

    Article  Google Scholar 

  • Jokipii, J.R., Cosmic-ray propagation. I. Charged particles in a random magnetic field, Astrophys. J., 1966, vol. 146, pp. 480–487.

    Article  Google Scholar 

  • Kennel, C.F. and Petschek, H.E., Limit on stably trapped particle fluxes, J. Geophys. Res., 1966, vol. 71, no. 1, pp. 1–28.

    Article  Google Scholar 

  • Kontar, E.P., Bian, N.H., Emslie, A.G., and Vilmer, N., Turbulent pitch-angle scattering and diffusive transport of hard x-ray-producing electrons in flaring coronal loops, Astrophys. J., 2014, vol. 780, no. 2, p. 176.10.

    Article  Google Scholar 

  • Melrose, D.B. and Brown, J.C., Precipitation in trap models for solar hard X-ray bursts, Mon. Not. R. Astron. Soc., 1976, vol. 176, pp. 15–30.

    Article  Google Scholar 

  • Petrosian, V. and Donaghy, T.Q., On the spatial distribution of hard X-rays from solar flare loops, Astrophys. J., 1999, vol. 527, no. 2, pp. 945–957.

    Article  Google Scholar 

  • Simões, P.J.A. and Kontar, E.P., Implications for electron acceleration and transport from non-thermal electron rates at looptop and footpoint sources in solar flares, Astron. Astrophys., 2013, vol. 551, p. A135.10.

  • Stepanov, A.V. and Tsap, Yu.T., The energetic-electron spectra and hard X-ray radiation of solar flares, Astron. Rep., 1999, vol. 43, no. 12, pp. 838–848.

    Google Scholar 

  • Stepanov, A.V. and Tsap, Yu.T., Electron-whistler interaction in coronal loops and radiation signatures, Sol. Phys., 2002, vol. 211, no. 1, pp. 135–154.

    Article  Google Scholar 

  • Stepanov, A.V., Yokoyama, T., Shibasaki, K., and Melnikov, V.F., Turbulent propagation of high-energy electrons in a solar coronal loop, Astron. Astrophys., 2007, vol. 465, no. 2, pp. 613–619.

    Article  Google Scholar 

  • Trakhtengerts, V.Yu. and Rycroft, M.J., Svistovye i al’fvenovskie tsiklotronnye mazery v kosmose (Whistler and Alfvèn Cyclotron Masers in Space), Moscow: FIZMATLIT, 2012.

    Google Scholar 

  • Tsap, Y., Kopylova, Y., Goldvarg, T., and Stepanov, A., Oscillating magnetic trap and non-thermal emission from solar flares, Publ. Astron. Soc. Japan, 2013, vol. 65, no. SP1, p. S6.6.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Central (Pulkovo) Astronomical Observatory, Russian Academy of Sciences, Pulkovskoe sh. 65, St. Petersburg, 196140, Russia

    Yu. T. Tsap, A. V. Stepanov & Yu. G. Kopylova

Authors
  1. Yu. T. Tsap
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. A. V. Stepanov
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Yu. G. Kopylova
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Yu. T. Tsap.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Tsap, Y.T., Stepanov, A.V. & Kopylova, Y.G. Accumulation of accelerated electrons in coronal loops and time delays of solar flare nonthermal emission. Geomagn. Aeron. 55, 979–982 (2015). https://doi.org/10.1134/S0016793215070269

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1134/S0016793215070269

Keywords

Search

Navigation