Coulomb Collisions And Electron Acceleration In Solar Flares

Cover Page

Cite item

Full Text

Open Access Open Access
Restricted Access Access granted
Restricted Access Subscription Access

Abstract

The acceleration of quasi-thermal particles by an electric field, whose velocity is greater than the thermal velocity, is considered in various interpretations for the dynamic brake force of electrons arising due to Coulomb collisions. It is shown that if the velocity of electrons exceeds the thermal velocity by a factor of two, then the forces of dynamic braking, taking into account electron-electron collisions (Spitzer approximation), and changes in the distribution function of background electrons under the influence of an electric field (Dreicer approximation), practically coincide. If the electric field is much smaller than the Dreicer field, then the Spitzer and Harrison (accounting both for electron-electron collisions and changes in the background electron distribution function) approaches match to within a coefficient. The implications of these results for the acceleration of quasi-thermal electrons in solar flares are discussed.

About the authors

Yu. T. Tsap

Crimean Astrophysical Observatory of RAS

Email: yur_crao@mail.ru
Nauchny, Crimea, Russia

A. V. Stepanov

Central Astronomical Observatory at Pulkovo of RAS

St. Petersburg, Russia

Yu. G. Kopylova

Central Astronomical Observatory at Pulkovo of RAS

Email: yul@gaoran.ru
St. Petersburg, Russia

T. B. Goldvarg

Kalmyk State University

Elista, Russia

References

  1. Battaglia A.F., Hudson H., Warmuth A., et al. The existence of hot X-ray onsets in solar flares, Astron. Astrophys., 2023, vol. 679, id. A139. https://doi.org/10.1051/0004-6361/202347706
  2. Benz A.O. Flare Observations // Living Rev. Sol. Phys., 2008, vol. 5, no. 1, id. 1. https://doi.org/10.12942/hsp-2008-1
  3. Cohen R.S., Spitzer L., and Routly P.Mor. The electrical conductivity of an ionized gas // Phys. Rev., 1950, vol. 80, no. 2, pp. 230–238. https://doi.org/10.1103/PhysRev.80.230
  4. da Silva D.F., Hui L., Simoes P.J.A., et al. Statistical analysis of the onset temperature of solar flares in 2010–2011 // Mon. Not. R. Astron. Soc., 2023, vol. 525, no. 3, pp. 4143–4148. https://doi.org/10.1093/mnras/stad2244
  5. Dreicer H. Electron and Ion Runaway in a Fully Ionized Gas. I // Phys. Rev., 1959, vol. 115, no. 2, pp. 238–249. https://doi.org/10.1103/PhysRev.115.238
  6. Fletcher L., Dennis B.R., Hudson H.S., et al. An observational overview of solar flares // Space Sci. Rev., 2011, vol. 159, no. 1–4, pp. 19–106. https://doi.org/10.1007/s11214-010-9701-8
  7. Gritsyk P.A. and Somov B.V. Modern analytic models of acceleration and propagation of electrons in solar flares // Physics-Uspekhi, 2023, vol. 66, no. 05, pp. 437–459. https://doi.org/10.3367/UFNe.2021.08.039048
  8. Harrison E.R. Runaway and suprathermal particles, Journal of Nuclear Energy. Part C // Plasma Physics, Accelerators, Thermonuclear Research, 1960, vol. 1, no. 3, pp. 105–115. https://doi.org/10.1088/0368-3281/1/3/301
  9. Holman G. DC electric field acceleration of ions in solar flares // Astrophys. J., 1995, vol. 452, pp. 451–456. https://doi.org/10.1086/176316
  10. Hoyng P., Brown J.C., and van Beek H.F. High time resolution analysis of solar hard X-ray flares observed on board the ESROTD-1A satellite // Sol. Phys., 1976, vol. 48, no. 2, pp. 197–254. https://doi.org/10.1007/BF00151992
  11. Hudson H.S., Simoes P.J.A., Fletcher L. et al. // Mon. Not. R. Astron. Soc., 2021, vol. 501, no. 1, pp. 1273–1281. https://doi.org/10.1093/mnras/staa3664
  12. Miller J.A., Cargill P.J., Emslie A.G., et al. Critical issues for understanding particle acceleration in impulsive solar flares // J. Geophys. Res., 1997, vol. 102, no. A7, pp. 14631–14660. https://doi.org/10.1029/971A00976
  13. Raymond J., Lin R.P., Krucker S., and Petrosian V. Observational Aspects of Particle Acceleration in Large Solar Flares // Space Sci. Rev., 2022, vol. 173, pp. 197–221. https://doi.org/10.1007/s11214-012-9897-x
  14. Spitzer L. Physics of Fully Ionized Gases, New York: Interscience (2nd edition), 1962.
  15. Stepanov A.V., Zaitsev V.V., and Kupriyanova E.G. Features of the Joule Dissipation in the Solar Atmosphere // Geomagn. Aeron., 2024, vol. 64, no. 8, pp. 1203–1214. https://doi.org/10.1134/S0016793224700300
  16. Tsap Yu.T. Mechanisms of electron acceleration in solar flares // Izv. Krymsk. Astrofiz. Observ., 2000, vol. 96, pp. 165–175.
  17. Tsap Yu.T., Melnikov V.F. Collisional Plasma Temperature and Betatron Acceleration of Quasi-thermal Electrons in Solar Flares, Astron. Lett., 2023, vol. 49, no. 4, pp. 200–208. https://doi.org/10.1134/S1063773723040059
  18. Tsap Yu.T., Stepanov A.V., Kopylova Yu.G. Dreicer electric field definition and runaway electrons in solar flares // Research in Astronomy and Astrophysics, 2024, vol. 24, no. 2, id. 025015. https://doi.org/10.1088/1674-4527/ad1bd5
  19. Veronig A., Vrsnak B., Temmer M., and Hanslmeier A. // Sol. Phys., 2002, vol. 208, no. 2, pp. 297–315. https://doi.org/10.1023/A:1020563804164

Supplementary files

Supplementary Files
Action
1. JATS XML
Download

Copyright (c) 2025 Russian Academy of Sciences

Согласие на обработку персональных данных

 

Используя сайт https://journals.rcsi.science, я (далее – «Пользователь» или «Субъект персональных данных») даю согласие на обработку персональных данных на этом сайте (текст Согласия) и на обработку персональных данных с помощью сервиса «Яндекс.Метрика» (текст Согласия).