Letter | Published:

Coalescence of magnetic flux ropes in the ion diffusion region of magnetic reconnection

Nature Physics volume 12, pages 263267 (2016) | Download Citation

Abstract

Magnetic reconnection is an important process in space1,2,3,4,5 and laboratory6 plasmas that effectively converts magnetic energy into plasma kinetic energy within a current sheet. Theoretical work7 suggested that reconnection occurs through the growth and overlap of magnetic flux ropes that deconstruct magnetic surfaces in the current sheet and enable the diffusion of the magnetic field lines between two sides of the sheet. This scenario was also proposed as a primary mechanism for accelerating energetic particles during reconnection8, but experimental evidence has remained elusive. Here, we identify a total of 19 flux ropes during reconnection in the magnetotail. We found that the majority of the ropes are embedded in the Hall magnetic field region and 63% of them are coalescing. These observations show that the diffusion region is filled with flux ropes and that their interaction is intrinsic to the reconnection dynamics, leading to turbulence.

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Acknowledgements

R.W. appreciates the valuable suggestions from W. Daughton at Los Alamos National Laboratory. All Cluster data other than the PEACE data are available at Cluster Science Archive (http://www.cosmos.esa.int/web/csa). We thank the FGM, CIS, EFW, PEACE, and RAPID instrument teams. This work is supported by the National Science Foundation of China (NSFC; grants 41474126, 41331067, 41174122, 11220101002 and 41104092) and by the National Basic Research Program of China (2014CB845903 and 2013CBA01503). This work at Austria is supported by the Austrian Science Fund (FWF) I429-N16.

Author information

Affiliations

  1. Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China

    • Rongsheng Wang
    •  & Aimin Du
  2. CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei 230026, China

    • Rongsheng Wang
    • , Quanming Lu
    • , Can Huang
    • , Mingyu Wu
    • , San Lu
    •  & Shui Wang
  3. Space Research Institute, Austrian Academy of Sciences, Graz 8042, Austria

    • Rumi Nakamura
  4. Los Alamos National Laboratory, PO Box 1663, Los Alamos, New Mexico 87545, USA

    • Fan Guo
  5. Space Science Centre (ANGKASA), Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, Malaysia

    • Waileong Teh

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Contributions

R.W. carried out data analysis, interpreted the results, and wrote the paper. Q.L. provided the theoretical analysis. Q.L., C.H., R.N., F.G., W.T., A.D. and S.W. participated in discussion and interpretation of the data. F.G. and Q.L. improved language of the manuscript. M.W. and S.L. participated in the earlier discussion. All of the authors made significant contributions to this work.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Rongsheng Wang or Quanming Lu.

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DOI

https://doi.org/10.1038/nphys3578

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