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Magnetic reconnection from a multiscale instability cascade


Magnetic reconnection, the process whereby magnetic field lines break and then reconnect to form a different topology, underlies critical dynamics of magnetically confined plasmas in both nature1,2,3,4 and the laboratory5,6,7,8,9. Magnetic reconnection involves localized diffusion of the magnetic field across plasma, yet observed reconnection rates are typically much higher than can be accounted for using classical electrical resistivity10. It is generally proposed10 that the field diffusion underlying fast reconnection results instead from some combination of non-magnetohydrodynamic processes that become important on the ‘microscopic’ scale of the ion Larmor radius or the ion skin depth. A recent laboratory experiment11 demonstrated a transition from slow to fast magnetic reconnection when a current channel narrowed to a microscopic scale, but did not address how a macroscopic magnetohydrodynamic system accesses the microscale. Recent theoretical models12 and numerical simulations13,14 suggest that a macroscopic, two-dimensional magnetohydrodynamic current sheet might do this through a sequence of repetitive tearing and thinning into two-dimensional magnetized plasma structures having successively finer scales. Here we report observations demonstrating a cascade of instabilities from a distinct, macroscopic-scale magnetohydrodynamic instability to a distinct, microscopic-scale (ion skin depth) instability associated with fast magnetic reconnection. These observations resolve the full three-dimensional dynamics and give insight into the frequently impulsive nature of reconnection in space and laboratory plasmas.

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Figure 1: Geometry of experimental set-up.
Figure 2: Growth of the amplitude of the kink instability.
Figure 3: Time series images of plasma jet evolution.


  1. Paschmann, G. et al. Plasma acceleration at the Earth’s magnetopause: evidence for reconnection. Nature 282, 243–246 (1979)

    Article  ADS  Google Scholar 

  2. Mikic, Z., Barnes, D. C. & Schnack, D. D. Dynamical evolution of a solar coronal magnetic field arcade. Astrophys. J. 328, 830–847 (1988)

    Article  ADS  Google Scholar 

  3. Colgate, S., Li, H. & Pariev, V. The origin of the magnetic fields of the universe: the plasma astrophysics of the free energy of the universe. Phys. Plasmas 8, 2425–2431 (2001)

    Article  ADS  CAS  Google Scholar 

  4. Uzdensky, D. A. & MacFadyen, A. I. Stellar explosions by magnetic towers. Astrophys. J. 647, 1192–1212 (2006)

    Article  ADS  CAS  Google Scholar 

  5. Wesson, J. A. Sawtooth reconnection. Nucl. Fusion 30, 2545–2549 (1990)

    Article  CAS  Google Scholar 

  6. Yamada, M. et al. Investigation of magnetic reconnection in a high-temperature tokamak plasma. Phys. Plasmas 1, 3269–3276 (1994)

    Article  ADS  CAS  Google Scholar 

  7. Bellan, P. M. Spheromaks 60–75 (Imperial Coll. Press, 2000)

    Book  Google Scholar 

  8. Taylor, J. B. Relaxation and magnetic reconnection. Rev. Mod. Phys. 58, 741–763 (1986)

    Article  ADS  CAS  Google Scholar 

  9. Brown, M. Experimental studies of magnetic reconnection. Phys. Plasmas 6, 1717–1724 (1999)

    Article  ADS  CAS  Google Scholar 

  10. Yamada, M., Kulsrud, R. & Ji, H. Magnetic reconnection. Rev. Mod. Phys. 82, 603–664 (2010)

    Article  ADS  Google Scholar 

  11. Egedal, J. et al. Laboratory observations of spontaneous magnetic reconnection. Phys. Rev. Lett. 98, 015003 (2007)

    Article  ADS  CAS  Google Scholar 

  12. Shibata, K. & Tanuma, S. Plasmoid-induced-reconnection and fractal reconnection. Earth Planets Space 53, 473–482 (2001)

    Article  ADS  Google Scholar 

  13. Che, H., Drake, J. F. & Swisdak, M. A current filamentation mechanism for breaking magnetic field lines during reconnection. Nature 474, 184–187 (2011)

    Article  ADS  CAS  Google Scholar 

  14. Drake, J. F. et al. Formation of secondary islands during magnetic reconnection. Geophys. Res. Lett. 303, L13105 (2006)

    Article  ADS  Google Scholar 

  15. Hsu, S. C. & Bellan, P. M. Experimental identification of the kink instability as a poloidal flux amplification mechanism for coaxial gun spheromak formation. Phys. Rev. Lett. 90, 215002 (2003)

    Article  ADS  CAS  Google Scholar 

  16. Chandrasekhar, S. Hydrodynamic and Hydromagnetic Stability 464–466 (Dover, 1961)

    MATH  Google Scholar 

  17. Gekelman, W. & Stenzel, R. L. Magnetic field line reconnection experiments: 6. Magnetic turbulence. J. Geophys. Res. 89, 2715–2733 (1984)

    Article  ADS  Google Scholar 

  18. Srivastava, A. K., Zaqarashvili, T. V., Kumar, P. & Khoachenko, M. L. Observation of kink instability during small B5.0 solar flare on 2007 June 4. Astrophys. J. 715, 292–299 (2010)

    Article  ADS  CAS  Google Scholar 

  19. Zhou, G. P. et al. Two successive coronal mass ejections driven by the kink and drainage instabilities of an eruptive prominence. Astrophys. J. 651, 1238–1244 (2006)

    Article  ADS  CAS  Google Scholar 

  20. Berger, T. et al. Magneto-thermal convection in solar prominences. Nature 472, 197–200 (2011)

    Article  ADS  CAS  Google Scholar 

  21. Liu, C. et al. The eruption from a sigmoidal solar active region on 2005 May 13. Astrophys. J. 669, 1372–1381 (2007)

    Article  ADS  CAS  Google Scholar 

  22. Kumar, D. & Bellan, P. M. Nonequilibrium Alfvénic plasma jets associated with spheromak formation. Phys. Rev. Lett. 103, 105003 (2009)

    Article  ADS  Google Scholar 

  23. Yun, G. S. & Bellan, P. M. Plasma tubes becoming collimated as a result of magnetohydrodynamic pumping. Phys. Plasmas 17, 062108 (2010)

    Article  ADS  Google Scholar 

  24. Hsu, S. C. & Bellan, P. M. A laboratory plasma experiment for studying magnetic dynamics of accretion discs and jets. Mon. Not. R. Astron. Soc. 334, 257–261 (2002)

    Article  ADS  Google Scholar 

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This work supported by the US DOE, NSF and AFOSR.

Author information

Authors and Affiliations



A.L.M. performed the experiments and analysed data. A.L.M. and P.M.B. discussed and interpreted the results and wrote the manuscript.

Corresponding author

Correspondence to Auna L. Moser.

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Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Figures

This file contains Supplementary Figures 1-5 with legends. They are fast camera images that show helical plasma geometry and plasma filament breaking; EUV diode data and capacitively coupled probe data highlight the difference in reconnecting and non reconnecting plasmas; fast camera image shows hydrogen does not reach miscrocale. (PDF 3175 kb)

Supplementary Movie 1

This movie shows an overview of the experiment: the plasma jet grows and then undergoes first a kink instability and then a Rayleigh-Taylor instability before reconnecting. (MOV 1143 kb)

Supplementary Movie 2

This movie version of Figure 3 shows the kink instability and Rayleigh-Taylor instability in greater detail. (MOV 577 kb)

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Moser, A., Bellan, P. Magnetic reconnection from a multiscale instability cascade. Nature 482, 379–381 (2012).

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