Transport of solar wind into Earth's magnetosphere through rolled-up Kelvin–Helmholtz vortices


Establishing the mechanisms by which the solar wind enters Earth's magnetosphere is one of the biggest goals of magnetospheric physics, as it forms the basis of space weather phenomena such as magnetic storms and aurorae1. It is generally believed that magnetic reconnection is the dominant process, especially during southward solar-wind magnetic field conditions when the solar-wind and geomagnetic fields are antiparallel at the low-latitude magnetopause2. But the plasma content in the outer magnetosphere increases during northward solar-wind magnetic field conditions3,4, contrary to expectation if reconnection is dominant. Here we show that during northward solar-wind magnetic field conditions—in the absence of active reconnection at low latitudes—there is a solar-wind transport mechanism associated with the nonlinear phase of the Kelvin–Helmholtz instability5. This can supply plasma sources for various space weather phenomena.

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Figure 1: Three-dimensional (3D) cutaway view of Earth's magnetosphere, showing signatures of Kelvin–Helmholtz instability (KHI).
Figure 2: Detection by Cluster of rolled-up plasma vortices on 20 November 2001 (20:26–20:42 ut).
Figure 3: The ion energy spectra and velocity distributions observed by C1, showing the coexistence of the solar-wind (cold) and magnetospheric (hot) populations.


  1. 1

    Akasofu, S.-I. Energy coupling between the solar wind and the magnetosphere. Space Sci. Rev. 28, 121–190 (1981)

    ADS  Article  Google Scholar 

  2. 2

    Cowley, S. W. H. in Magnetic Reconnection in Space and Laboratory Plasmas (ed. Hones, E. W.) 375–378 (Geophys. Monograph 30, American Geophysical Union, Washington DC, 1984)

    Google Scholar 

  3. 3

    Mitchell, D. G. et al. An extended study of the low-latitude boundary layer on the dawn and dusk flanks of the magnetosphere. J. Geophys. Res. 92, 7394–7404 (1987)

    ADS  Article  Google Scholar 

  4. 4

    Hasegawa, H., Fujimoto, M., Saito, Y. & Mukai, T. Dense and stagnant ions in the low-latitude boundary region under northward interplanetary magnetic field. Geophys. Res. Lett. 31, L06802 (2004)

    ADS  Google Scholar 

  5. 5

    Chandrasekhar, S. Hydrodynamic and Hydromagnetic Stability (Oxford Univ. Press, New York, 1961)

    Google Scholar 

  6. 6

    Sckopke, N. G. et al. Structure of the low-latitude boundary layer. J. Geophys. Res. 86, 2099–2110 (1981)

    ADS  Article  Google Scholar 

  7. 7

    Song, P. & Russell, C. T. Model of the formation of the low-latitude boundary-layer for strongly northward interplanetary magnetic-field. J. Geophys. Res. 97, 1411–1420 (1992)

    ADS  Article  Google Scholar 

  8. 8

    Sibeck, D. G. et al. in Magnetospheric Plasma Sources and Losses Ch. 5 (ed. Hultqvist, B.) 207–283 (Space Sciences Series of ISSI 6, Kluwer Academic, Dordrecht, 1999)

    Google Scholar 

  9. 9

    Dungey, J. W. in Proc. Ionosphere Conf. 225 (Physical Society of London, 1955).

  10. 10

    Miura, A. Anomalous transport by magnetohydrodynamic Kelvin-Helmholtz instabilities in the solar wind-magnetosphere interaction. J. Geophys. Res. 89, 801–818 (1984)

    ADS  Article  Google Scholar 

  11. 11

    Thomas, V. A. & Winske, D. Kinetic simulations of the Kelvin-Helmholtz instability at the magnetopause. J. Geophys. Res. 98, 11425–11438 (1993)

    ADS  Article  Google Scholar 

  12. 12

    Fujimoto, M. & Terasawa, T. Anomalous ion mixing within an MHD scale Kelvin-Helmholtz vortex. J. Geophys. Res. 99, 8601–8613 (1994)

    ADS  Article  Google Scholar 

  13. 13

    Huba, J. D. The Kelvin-Helmholtz instability: Finite Larmor radius magnetohydrodynamics. Geophys. Res. Lett. 23, 2907–2910 (1996)

    ADS  Article  Google Scholar 

  14. 14

    Nykyri, K. & Otto, A. Plasma transport at the magnetospheric boundary due to reconnection in Kelvin-Helmholtz vortices. Geophys. Res. Lett. 28, 3565–3568 (2001)

    ADS  CAS  Article  Google Scholar 

  15. 15

    Matsumoto, Y. & Hoshino, M. Onset of turbulence induced by a Kelvin-Helmholtz vortex. Geophys. Res. Lett. 31, L02807 (2004)

    ADS  Article  Google Scholar 

  16. 16

    Nakamura, T. K. M., Hayashi, D., Fujimoto, M. & Shinohara, I. Decay of MHD-scale Kelvin-Helmholtz vortices mediated by parasitic electron dynamics. Phys. Rev. Lett. 92, 145001 (2004)

    ADS  CAS  Article  Google Scholar 

  17. 17

    Ogilvie, K. W. & Fitzenreiter, R. J. The Kelvin-Helmholtz instability at the magnetopause and inner boundary layer surface. J. Geophys. Res. 94, 15113–15123 (1989)

    ADS  Article  Google Scholar 

  18. 18

    Kivelson, G. K. & Chen, S.-H. in Physics of the Magnetopause (eds Song, P., Sonnerup, B. U. Ö. & Thomsen, M. F.) 257–268 (Geophys. Monograph 90, American Geophysical Union, Washington DC, 1995)

    Google Scholar 

  19. 19

    Hones, E. W. Jr et al. Further determination of the characteristics of magnetospheric plasma vortices. J. Geophys. Res. 86, 814–820 (1981)

    ADS  Article  Google Scholar 

  20. 20

    Fairfield, D. H. et al. Geotail observations of the Kelvin-Helmholtz instability at the equatorial magnetotail boundary for parallel northward fields. J. Geophys. Res. 105, 21159–21173 (2000)

    ADS  Article  Google Scholar 

  21. 21

    Fujimoto, M., Tonooka, T. & Mukai, T. in Earth's Low-latitude Boundary Layer (eds Newell, P. T. & Onsager, T.) 241–251 (Geophys. Monograph 133, American Geophysical Union, Washington DC, 2003)

    Google Scholar 

  22. 22

    Miura, A. Dependence of the magnetopause Kelvin-Helmholtz instability on the orientation of the magnetosheath magnetic field. Geophys. Res. Lett. 22, 2993–2996 (1995)

    ADS  Article  Google Scholar 

  23. 23

    Lemaire, J. Impulsive penetration of filamentary plasma elements into magnetospheres of Earth and Jupiter. Planet. Space Sci. 25, 887–890 (1977)

    ADS  Article  Google Scholar 

  24. 24

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

    ADS  Article  Google Scholar 

  25. 25

    Phan, T.-D. et al. Extended magnetic reconnection at the Earth's magnetopause from detection of bi-directional jets. Nature 404, 848–850 (2000)

    ADS  CAS  Article  Google Scholar 

  26. 26

    Fuselier, S. A. in Physics of the Magnetopause (eds Song, P., Sonnerup, B. U. Ö. & Thomsen, M. F.) 181–187 (Geophys. Monograph 90, American Geophysical Union, Washington DC, 1995)

    Google Scholar 

  27. 27

    Kessel, R. L. et al. Evidence of high-latitude reconnection during northward IMF: Hawkeye observations. Geophys. Res. Lett. 23, 583–586 (1996)

    ADS  Article  Google Scholar 

  28. 28

    Miura, A. & Pritchett, P. L. Nonlocal stability analysis of the MHD Kelvin-Helmholtz instability in a compressible plasma. J. Geophys. Res. 87, 7431–7444 (1982)

    ADS  Article  Google Scholar 

  29. 29

    Report of the NASA Science and Technology Definition Team for the Magnetospheric Multiscale (MMS) Mission (NASA/TM-2000-209883, Goddard Space Flight Center, Greenbelt, MD, 1999).

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We are indebted to the Cluster team for the design and successful operation of the Cluster II mission. Part of this work was done while H.H. visited UC Berkeley.

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Correspondence to H. Hasegawa.

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The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Figure

Relation between the x components of the ion bulk velocity and of the local Alfvén velocity during the observation of the vortices, indicating the absence of local reconnection near the vortices. (DOC 73 kb)

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Hasegawa, H., Fujimoto, M., Phan, T. et al. Transport of solar wind into Earth's magnetosphere through rolled-up Kelvin–Helmholtz vortices. Nature 430, 755–758 (2004).

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