Solar Physics

, Volume 291, Issue 5, pp 1385–1404

Particle Acceleration in Collapsing Magnetic Traps with a Braking Plasma Jet

  • Alexei Borissov
  • Thomas Neukirch
  • James Threlfall
Article

Abstract

Collapsing magnetic traps (CMTs) are one proposed mechanism for generating non-thermal particle populations in solar flares. CMTs occur if an initially stretched magnetic field structure relaxes rapidly into a lower-energy configuration, which is believed to happen as a by-product of magnetic reconnection. A similar mechanism for energising particles has also been found to operate in the Earth’s magnetotail. One particular feature proposed to be of importance for particle acceleration in the magnetotail is that of a braking plasma jet, i.e. a localised region of strong flow encountering stronger magnetic field which causes the jet to slow down and stop. Such a feature has not been included in previously proposed analytical models of CMTs for solar flares. In this work we incorporate a braking plasma jet into a well studied CMT model for the first time. We present results of test particle calculations in this new CMT model. We observe and characterise new types of particle behaviour caused by the magnetic structure of the jet braking region, which allows electrons to be trapped both in the braking jet region and the loop legs. We compare and contrast the behaviour of particle orbits for various parameter regimes of the underlying trap by examining particle trajectories, energy gains and the frequency with which different types of particle orbit are found for each parameter regime.

Keywords

Flares, energetic particles Energetic particles, electrons Magnetic reconnection, models 

References

  1. Artemyev, A.V.: 2014, Charged-particle acceleration in braking plasma jets. Phys. Rev. E 89, 033108. DOI. http://link.aps.org/doi/10.1103/PhysRevE.89.033108. ADSCrossRefGoogle Scholar
  2. Birn, J., Hesse, M.: 1996, Details of current disruption and diversion in simulations of magnetotail dynamics. J. Geophys. Res. 101, 15345. DOI. ADS. ADSCrossRefGoogle Scholar
  3. Birn, J., Artemyev, A.V., Baker, D.N., Echim, M., Hoshino, M., Zelenyi, L.M.: 2012, Particle acceleration in the magnetotail and aurora. Space Sci. Rev. 173(1–4), 49. DOI. http://dx.doi.org/10.1007/s11214-012-9874-4. ADSCrossRefGoogle Scholar
  4. Bogachev, S.A., Somov, B.V.: 2001, Acceleration of charged particles in collapsing magnetic traps during solar flares. Astron. Rep. 45, 157. DOI. ADS. ADSCrossRefGoogle Scholar
  5. Bogachev, S.A., Somov, B.V.: 2005, Comparison of the Fermi and betatron acceleration efficiencies in collapsing magnetic traps. Astron. Lett. 31, 537. DOI. ADS. ADSCrossRefGoogle Scholar
  6. Bogachev, S.A., Somov, B.V.: 2007, Formation of power-law electron spectra in collapsing magnetic traps. Astron. Lett. 33, 54. DOI. ADS. ADSCrossRefGoogle Scholar
  7. Bogachev, S.A., Somov, B.V.: 2009, Effect of Coulomb collisions on the particle acceleration in collapsing magnetic traps. Astron. Lett. 35, 57. DOI. ADS. ADSCrossRefGoogle Scholar
  8. Cargill, P.J.: 1991, The interaction of collisionless shocks in astrophysical plasmas. Astrophys. J. 376, 771. DOI. ADS. ADSCrossRefGoogle Scholar
  9. Cargill, P.J., Vlahos, L., Baumann, G., Drake, J.F., Nordlund, Å.: 2012, Current fragmentation and particle acceleration in solar flares. Space Sci. Rev. 173, 223. DOI. ADS. ADSCrossRefGoogle Scholar
  10. Cash, J.R., Karp, A.H.: 1990, A variable order Runge–Kutta method for initial-value problems with rapidly varying right-hand sides. ACM Trans. Math. Softw. 16, 201. DOI. MathSciNetCrossRefMATHGoogle Scholar
  11. Chen, B., Bastian, T.S., Shen, C., Gary, D.E., Krucker, S., Glesener, L.: 2015, Particle acceleration by a solar flare termination shock. Science 350, 1238. DOI. ADS. ADSCrossRefGoogle Scholar
  12. Eradat Oskoui, S., Neukirch, T.: 2014, Particle energisation in a collapsing magnetic trap model: the relativistic regime. Astron. Astrophys. 567, A131. DOI. ADS. ADSCrossRefGoogle Scholar
  13. Eradat Oskoui, S., Neukirch, T., Grady, K.J.: 2014, Loss cone evolution and particle escape in collapsing magnetic trap models in solar flares. Astron. Astrophys. 563, A73. DOI. ADS. ADSCrossRefGoogle Scholar
  14. Fu, H.S., Cao, J.B., Khotyaintsev, Y.V., Sitnov, M.I., Runov, A., Fu, S.Y., Hamrin, M., André, M., Retinò, A., Ma, Y.D., Lu, H.Y., Wei, X.H., Huang, S.Y.: 2013, Dipolarization fronts as a consequence of transient reconnection: In situ evidence. Geophys. Res. Lett. 40, 6023. DOI. ADS. ADSCrossRefGoogle Scholar
  15. Giuliani, P., Neukirch, T., Wood, P.: 2005, Particle motion in collapsing magnetic traps in solar flares. I. Kinematic theory of collapsing magnetic traps. Astrophys. J. 635, 636. DOI. ADS. ADSCrossRefGoogle Scholar
  16. Gordovskyy, M., Browning, P.K., Vekstein, G.E.: 2010a, Particle acceleration in a transient magnetic reconnection event. Astron. Astrophys. 519, A21. DOI. ADS. ADSCrossRefGoogle Scholar
  17. Gordovskyy, M., Browning, P.K., Vekstein, G.E.: 2010b, Particle acceleration in fragmenting periodic reconnecting current sheets in solar flares. Astrophys. J. 720, 1603. DOI. ADS. ADSCrossRefGoogle Scholar
  18. Grady, K.J., Neukirch, T.: 2009, An extension of the theory of kinematic MHD models of collapsing magnetic traps to 2.5D with shear flow and to 3D. Astron. Astrophys. 508, 1461. DOI. ADS. ADSCrossRefGoogle Scholar
  19. Grady, K.J., Neukirch, T., Giuliani, P.: 2012, A systematic examination of particle motion in a collapsing magnetic trap model for solar flares. Astron. Astrophys. 546, A85. DOI. ADS. ADSCrossRefGoogle Scholar
  20. Imada, S., Nakamura, R., Daly, P.W., Hoshino, M., Baumjohann, W., Mühlbachler, S., Balogh, A., Rème, H.: 2007, Energetic electron acceleration in the downstream reconnection outflow region. J. Geophys. Res. (Space Phys.) 112, A03202. DOI. ADS. ADSCrossRefGoogle Scholar
  21. Karlický, M., Bárta, M.: 2006, X-ray loop-top source generated by processes in a flare collapsing trap. Astrophys. J. 647, 1472. DOI. ADS. ADSCrossRefGoogle Scholar
  22. Karlický, M., Kosugi, T.: 2004, Acceleration and heating processes in a collapsing magnetic trap. Astron. Astrophys. 419, 1159. DOI. ADS. ADSCrossRefGoogle Scholar
  23. Khotyaintsev, Y.V., Cully, C.M., Vaivads, A., André, M., Owen, C.J.: 2011, Plasma jet braking: Energy dissipation and nonadiabatic electrons. Phys. Rev. Lett. 106, 165001. DOI. http://link.aps.org/doi/10.1103/PhysRevLett.106.165001. ADSCrossRefGoogle Scholar
  24. Litvinenko, Y.E.: 1996, Particle acceleration in reconnecting current sheets with a nonzero magnetic field. Astrophys. J. 462, 997. DOI. ADS. ADSCrossRefGoogle Scholar
  25. Mann, G., Warmuth, A., Aurass, H.: 2009, Generation of highly energetic electrons at reconnection outflow shocks during solar flares. Astron. Astrophys. 494, 669. DOI. ADS. ADSCrossRefMATHGoogle Scholar
  26. Miller, J.A., Cargill, P.J., Emslie, A.G., Holman, G.D., Dennis, B.R., LaRosa, T.N., Winglee, R.M., Benka, S.G., Tsuneta, S.: 1997, Critical issues for understanding particle acceleration in impulsive solar flares. J. Geophys. Res. 102, 14631. DOI. ADS. ADSCrossRefGoogle Scholar
  27. Minoshima, T., Masuda, S., Miyoshi, Y.: 2010, Drift-kinetic modeling of particle acceleration and transport in solar flares. Astrophys. J. 714, 332. DOI. ADS. ADSCrossRefGoogle Scholar
  28. Minoshima, T., Masuda, S., Miyoshi, Y., Kusano, K.: 2011, Coronal electron distribution in solar flares: Drift-kinetic model. Astrophys. J. 732, 111. DOI. ADS. ADSCrossRefGoogle Scholar
  29. Miteva, R., Mann, G.: 2007, The electron acceleration at shock waves in the solar corona. Astron. Astrophys. 474, 617. DOI. ADS. ADSCrossRefMATHGoogle Scholar
  30. Northrop, T.G.: 1963, The Adiabatic Motion of Charged Particles, John Wiley & Sons, Inc., New York. MATHGoogle Scholar
  31. Shibata, K., Magara, T.: 2011, Solar flares: Magnetohydrodynamic processes. Living Rev. Solar Phys. 8, 6. DOI. ADS. ADSCrossRefGoogle Scholar
  32. Sitnov, M.I., Swisdak, M.: 2011, Onset of collisionless magnetic reconnection in two-dimensional current sheets and formation of dipolarization fronts. J. Geophys. Res. 116, 12216. DOI. ADS. CrossRefGoogle Scholar
  33. Somov, B.V., Bogachev, S.A.: 2003, The betatron effect in collapsing magnetic traps. Astron. Lett. 29, 621. DOI. ADS. ADSCrossRefGoogle Scholar
  34. Somov, B.V., Kosugi, T.: 1997, Collisionless reconnection and high-energy particle acceleration in solar flares. Astrophys. J. 485, 859. ADS. ADSCrossRefGoogle Scholar
  35. Threlfall, J., Neukirch, T., Parnell, C.E., Eradat Oskoui, S.: 2015a, Particle acceleration at a reconnecting magnetic separator. Astron. Astrophys. 574, A7. DOI. ADS. ADSCrossRefGoogle Scholar
  36. Threlfall, J., Bourdin, P.-A., Neukirch, T., Parnell, C.E.: 2016, Particle dynamics in a non-flaring solar active region model. Astron. Astrophys. 587, A4. ADS. ADSCrossRefGoogle Scholar
  37. Tsuneta, S., Naito, T.: 1998, Fermi acceleration at the fast shock in a solar flare and the impulsive loop-top hard X-ray source. Astrophys. J. Lett. 495, L67. DOI. ADS. ADSCrossRefGoogle Scholar
  38. Wood, P., Neukirch, T.: 2005, Electron acceleration in reconnecting current sheets. Solar Phys. 226, 73. DOI. ADS. ADSCrossRefGoogle Scholar
  39. Zharkova, V.V., Arzner, K., Benz, A.O., Browning, P., Dauphin, C., Emslie, A.G., Fletcher, L., Kontar, E.P., Mann, G., Onofri, M., Petrosian, V., Turkmani, R., Vilmer, N., Vlahos, L.: 2011, Recent advances in understanding particle acceleration processes in solar flares. Space Sci. Rev. 159, 357. DOI. ADS. ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  • Alexei Borissov
    • 1
  • Thomas Neukirch
    • 1
  • James Threlfall
    • 1
  1. 1.School of Mathematics and StatisticsUniversity of St AndrewsSt AndrewsUK

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