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Observations and simulations of non-local acceleration of electrons in magnetotail magnetic reconnection events

Abstract

Magnetic reconnection in magnetized plasmas represents a change in magnetic field topology and is associated with a concomitant energization of charged particles that results from a conversion of magnetic energy into particle energy. In Earth’s magnetosphere this process is associated with the entry of the solar wind into the magnetosphere and with the initiation of auroral substorms. Using data from the THEMIS mission, together with global and test particle simulations, we demonstrate that electrons are energized in two distinct regions: a low-energy population (less than or equal to a few kiloelectronvolts) that arises in a diffusion region where particles are demagnetized and the magnetic topology changes, and a high-energy component (approaching 100 keV) that results from betatron acceleration within dipolarization fronts that sweep towards the inner magnetosphere far from the diffusion region. Thus, the observed particle energization is associated with both magnetic reconnection and with betatron acceleration associated with macroscopic flows.

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Figure 1: Observations from THEMIS P4 on 15 February 2008.
Figure 2: Bz component of the magnetic field and flows in the maximum pressure surface.
Figure 3: Simulated energy fluxes and observed energy fluxes from THEMIS P4 observations.
Figure 4: Plots of differential energy flux on the maximum pressure surface for two different energy channels.
Figure 5: Estimated change in the perpendicular energy flux from betatron acceleration in the simulation.

References

  1. Sarris, E. T., Krimigis, S. M. & Armstrong, T. P. Observations of magnetospheric bursts of high-energy protons and electrons at approximately at 35 RE with Imp 7. J. Geophys. Res. 81, 2341–2355 (1976).

    Article  ADS  Google Scholar 

  2. Kivelson, M. G. Summary remarks on the July 29, 1972 event. EOS 61, 335 (1980).

    Google Scholar 

  3. Baker, D. N. et al. Observation and modelling of energetic particles at synchronous orbit on July 29, 1977. J. Geophys. Res. 87, 5917–5932 (1982).

    Article  ADS  Google Scholar 

  4. Sato, T., Matsumoto, H. & Nagai, K. Particle acceleration in time-developing magnetic reconnection process. J. Geophys. Res. 87, 6089–6097 (1982).

    Article  ADS  Google Scholar 

  5. Åsnes, A. et al. Multispacecraft observation of electron beam in reconnection region. J. Geophys. Res. 113, A07S30 (2008).

    Google Scholar 

  6. Runov, A. et al. THEMIS observations of an earthward-propagating dipolarization front. Geophys. Res. Lett. 36, L14106 (2009).

    Article  ADS  Google Scholar 

  7. Asano, Y. et al. Electron acceleration signatures in the magnetotail associated with substorms. J. Geophys. Res. 115, A05215 (2010).

    Article  ADS  Google Scholar 

  8. Ashour-Abdalla, M. in Modern Challenges in Nonlinear Plasma Physics: A Festschrift Honoring the Career of Dennis Papadopoulos (eds Vassiliadis, D., Fung, S. F., Shao, X., Daglis, I. A. & Huba, J. D.) 196–207 (AIP Conf. Proc. 1320, American Institute of Physics, 2010).

    Google Scholar 

  9. Ashour-Abdalla, M., Bosqued, J. M., El-Alaoui, M., Peroomian, V. & Walker, R. Observations and simulations of a highly structured plasma sheet during northward IMF. J. Geophys. Res. 115, A10227 (2010).

    Article  ADS  Google Scholar 

  10. Deng, X. et al. Wave and particle characteristics of earthward electron injections associated with dipolarization fronts. J. Geophys. Res. 115, A09225 (2010).

    Article  ADS  Google Scholar 

  11. Øieroset, M., Lin, R. P., Phan, T. D., Larson, D. E. & Bale, S. D. Evidence for electron acceleration up to 300 keV in the magnetic reconnection diffusion region of Earth’s magnetotail. Phys. Rev. Lett. 89, 195001 (2002).

    Article  ADS  Google Scholar 

  12. Pritchett, P. L. Relativistic electron production during driven magnetic reconnection. Geophys. Res. Lett. 33, L13104 (2006).

    Article  ADS  Google Scholar 

  13. Pritchett, P. L. Relativistic electron production during guide field magnetic reconnection. J. Geophys. Res. 111, A10212 (2006).

    Article  ADS  Google Scholar 

  14. Hoshino, M. Electron surfing acceleration in magnetic reconnection. J. Geophys. Res. 110, A10215 (2005).

    Article  ADS  Google Scholar 

  15. Retinò, A. et al. Cluster observations of energetic electrons and electromagnetic fields within a reconnecting thin current sheet in the Earth’s magnetotail. J. Geophys. Res. 113, A12215 (2008).

    Article  ADS  Google Scholar 

  16. Imada, S. et al. Energetic electron acceleration in the downstream reconnection outflow region. J. Geophys. Res. 112, A03202 (2007).

    Article  ADS  Google Scholar 

  17. Birn, J. et al. Substorm electron injections: Geosynchronous observations and test particle simulations. J. Geophys. Res. 103, 9235–9248 (1998).

    Article  ADS  Google Scholar 

  18. Zhou, M. et al. THEMIS observation of multiple dipolarization fronts and associated wave characteristics in the near-Earth magnetotail. Geophys. Res. Lett. 36, L20107 (2009).

    Article  ADS  Google Scholar 

  19. Ambrosiano, J., Matthaeus, W. & Goldstein, M. Test-particle studies of acceleration by turbulent reconnection fields. J. Geophys. Res. 93, 14383–14400 (1988).

    Article  ADS  Google Scholar 

  20. Hesse, M., Kuznetsova, M. & Hoshino, M. The structure of the dissipation region for component reconnection: Particle simulations. Geophys. Res. Lett. 29, 1563 (2002).

    Article  ADS  Google Scholar 

  21. Pritchett, P. L. & Coroniti, F. V. Three-dimensional collisionless magnetic reconnection in the presence of a guide field. J. Geophys. Res. 109, A01220 (2004).

    Article  ADS  Google Scholar 

  22. Drake, J. F., Swisdak, M., Che, H. & Shay, M. A. Electron acceleration from contracting magnetic islands during reconnection. Nature 443, 553–556 (2006).

    Article  ADS  Google Scholar 

  23. Drake, J. F. et al. Formation of electron holes and particle energization during magnetic reconnection. Science 299, 873–877 (2003).

    Article  ADS  Google Scholar 

  24. Drake, J. F., Shay, M. A., Thongthai, W. & Swisdak, M. Production of energetic electrons during magnetic reconnection. Phys. Rev. Lett. 94, 095001 (2005).

    Article  ADS  Google Scholar 

  25. Kowal, G., Lazarian, A., Vishniac, E. T. & Otmianowska-Mazur, K. Numerical tests of fast reconnection in weakly stochastic magnetic fields. Astrophys. J. 700, 63–85 (2009).

    Article  ADS  Google Scholar 

  26. Shinohara, I. et al. Low-frequency electromagnetic turbulence observed near the substorm onset site. J. Geophys. Res. 103, 20365–20388 (1998).

    Article  ADS  Google Scholar 

  27. Hoshino, M., Mukai, T., Terasawa, T. & Shinohara, I. Superthermal electron acceleration in magnetic reconnection. J. Geophys. Res. 106, 25979–25978 (2001).

    Article  ADS  Google Scholar 

  28. Auster, H. U. et al. The THEMIS fluxgate magnetometer. Space Sci. Rev. 141, 235–264 (2008).

    Article  ADS  Google Scholar 

  29. Angelopoulos, V. The THEMIS mission. Space Sci. Rev. 141, 5–34 (2008).

    Article  ADS  Google Scholar 

  30. McFadden, J. P. et al. THEMIS ESA first science results and performance issues. Space Sci. Rev. 141, 477–508 (2008).

    Article  ADS  Google Scholar 

  31. Bonnell, J. W. et al. The electric field instrument (EFI) for THEMIS. Space Sci. Rev. 141, 303–341 (2008).

    Article  ADS  Google Scholar 

  32. Le Contel, O. et al. First results of the THEMIS search coil magnetometers. Space Sci. Rev. 141, 509–534 (2008).

    Article  ADS  Google Scholar 

  33. El-Alaoui, M. et al. Substorm evolution as revealed by THEMIS satellites and a global MHD simulation. J. Geophys. Res. 114, A08221 (2009).

    Article  ADS  Google Scholar 

  34. Ashour-Abdalla, M., El-Alaoui, M., Coroniti, F. V., Walker, R. J. & Peroomian, V. A new convection state at substorm onset: Results from an MHD study. Geophys. Res. Lett. 20, 1965 (2002).

    ADS  Google Scholar 

  35. Ashour-Abdalla, M., Berchem, J. P., Büchner, J. & Zelenyi, L. M. Shaping of the magnetotail from the mantle—Global and local structuring. J. Geophys. Res. 98, 5651–5676 (1993).

    Article  ADS  Google Scholar 

  36. Schriver, D., Ashour-Abdalla, M. & Richard, R. L. On the origin of the ion-electron temperature difference in the plasma sheet. J. Geophys. Res. 103, 14879–14896 (1998).

    Article  ADS  Google Scholar 

  37. Schriver, D. et al. in Proceedings of the 7th ISSS 345–346 (Research Institute for Sustainable Humanosphere (RISH), Kyoto University, 2005).

    Google Scholar 

  38. Büchner, J. & Zelenyi, L. M. Chaotization of the electron motion as the cause of an internal magnetotail instability and substorm onset. J. Geophys. Res. 92, 13456–13466 (1987).

    Article  ADS  Google Scholar 

  39. Büchner, J. & Zelenyi, L. M. Regular and chaotic charged particle motion in magnetotaillike field reversals. I—Basic theory of trapped motion. J. Geophys. Res. 94, 11821–11842 (1989).

    Article  ADS  Google Scholar 

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Acknowledgements

We thank H. Kohne for help with programming and display of the data and simulation results. Research at UCLA was supported by NASA grant NNX08AO48G. We acknowledge NASA contract NAS5-02099 and V. Angelopoulos for use of data from the THEMIS Mission, specifically, C. W. Carlson and J. P. McFadden for the use of ESA data, D. Larson and R. P. Lin for the use of SST data, K. H. Glassmeier, U. Auster and W. Baumjohann for the use of FGM data, J. W. Bonnell and F. S. Mozer for the use of EFI data, and A. Roux and O. LeContel for the use of SCM data. K-J.H. and M.L.G. were supported, in part, by NASA’s Magnetospheric Multiscale and Cluster missions at the Goddard Space Flight Center. M.G.K. was supported, in part, by NASA Grant UCB NAS 5-02099. The computing was carried out on NASA’s Columbia Supercomputer.

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Authors and Affiliations

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Contributions

M.A-A. initiated the electron acceleration study using observations and simulations. She led the research project, participated in the analysis of all of the simulation and observation results. M.E-A. carried out the MHD simulations and identified the dipolarization fronts in the Global model. He also participated in the analysis. M.G. was the first to realize the importance of this study. From his experience of Cluster data, he realized the wide applicability of these results. M.Z. carried out the particle simulations and participated in the analysis of the particle results. D.S. participated in the analysis of the particle results. R.R. developed the algorithm for converting simulation counting rates into differential energy flux and carried out the betatron acceleration analysis. R.W. participated in the analysis of the simulation results with emphasis on the MHD results. M.G.K. helped with theoretical issues; in particular she suggested analysis to quantify the betatron acceleration. K-J.H. applied experience she gained from studying electron acceleration during other dipolarization events seen by Cluster.

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Correspondence to Maha Ashour-Abdalla.

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Ashour-Abdalla, M., El-Alaoui, M., Goldstein, M. et al. Observations and simulations of non-local acceleration of electrons in magnetotail magnetic reconnection events. Nature Phys 7, 360–365 (2011). https://doi.org/10.1038/nphys1903

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