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A complex dynamo inferred from the hemispheric dichotomy of Jupiter’s magnetic field

Abstract

The Juno spacecraft, which is in a polar orbit around Jupiter, is providing direct measurements of the planet’s magnetic field close to its surface1. A recent analysis of observations of Jupiter’s magnetic field from eight (of the first nine) Juno orbits has provided a spherical-harmonic reference model (JRM09)2 of Jupiter’s magnetic field outside the planet. This model is of particular interest for understanding processes in Jupiter’s magnetosphere, but to study the field within the planet and thus the dynamo mechanism that is responsible for generating Jupiter’s main magnetic field, alternative models are preferred. Here we report maps of the magnetic field at a range of depths within Jupiter. We find that Jupiter’s magnetic field is different from all other known planetary magnetic fields. Within Jupiter, most of the flux emerges from the dynamo region in a narrow band in the northern hemisphere, some of which returns through an intense, isolated flux patch near the equator. Elsewhere, the field is much weaker. The non-dipolar part of the field is confined almost entirely to the northern hemisphere, so there the field is strongly non-dipolar and in the southern hemisphere it is predominantly dipolar. We suggest that Jupiter’s dynamo, unlike Earth’s, does not operate in a thick, homogeneous shell, and we propose that this unexpected field morphology arises from radial variations, possibly including layering, in density or electrical conductivity, or both.

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Fig. 1: The radial component of Jupiter’s magnetic field.
Fig. 2: Magnetic field lines.
Fig. 3: Non-dipole radial field.

References

  1. Connerney, J. E. P. et al. The Juno magnetic field investigation. Space Sci. Rev. 213, 39–138 (2017).

    ADS  Article  Google Scholar 

  2. Connerney, J. E. P. et al. A new model of Jupiter’s magnetic field from Juno’s first nine orbits. Geophys. Res. Lett. 45, 2590–2596 (2018).

    ADS  Article  Google Scholar 

  3. Liu, J., Goldreich, P. M. & Stevenson, D. J. Constraints on deep-seated zonal winds inside Jupiter and Saturn. Icarus 196, 653–664 (2008).

    ADS  Article  Google Scholar 

  4. Gastine, T., Wicht, J., Duarte, L., Heimpel, M. & Becker, A. Explaining Jupiter’s magnetic field and equatorial jet dynamics. Geophys. Res. Lett. 41, 5410–5419 (2014).

    ADS  Article  Google Scholar 

  5. Cao, H. & Stevenson, D. J. Zonal flow magnetic field interaction in the semi-conducting region of giant planets. Icarus 296, 59–72 (2017).

    ADS  Article  Google Scholar 

  6. Nellis, W. J., Weir, S. T. & Mitchell, A. C. Metallization and electrical conductivity of hydrogen in Jupiter. Science 273, 936–938 (1996).

    ADS  Article  PubMed  CAS  Google Scholar 

  7. French, M. et al. Ab initio simulations for material properties along the Jupiter adiabat. Astrophys. J. Suppl. Ser. 202, 5 (2012).

    ADS  Article  CAS  Google Scholar 

  8. Shure, L., Parker, R. L. & Backus, G. E. Harmonic splines for geomagnetic modelling. Phys. Earth Planet. Inter. 28, 215–229 (1982).

    ADS  Article  Google Scholar 

  9. Moore, K. M., Bloxham, J., Connerney, J. E. P., Jørgensen, J. L. & Merayo, J. M. G. The analysis of initial Juno magnetometer data using a sparse magnetic field representation. Geophys. Res. Lett. 44, 4687–4693 (2017).

    ADS  Article  Google Scholar 

  10. Christensen, U. R. & Aubert, J. Scaling properties of convection-driven dynamos in rotating spherical shells and application to planetary magnetic fields. Geophys. J. Int. 166, 97–114 (2006).

    ADS  Article  Google Scholar 

  11. Jones, C. A. A dynamo model of Jupiter’s magnetic field. Icarus 241, 148–159 (2014).

    ADS  Article  Google Scholar 

  12. Ridley, V. A. & Holme, R. Modeling the Jovian magnetic field and its secular variation using all available magnetic field observations. J. Geophys. Res. Planets 121, 309–337 (2016).

    ADS  Article  Google Scholar 

  13. Jones, C. A. Planetary magnetic fields and fluid dynamos. Annu. Rev. Fluid Mech. 43, 583–614 (2011).

    ADS  MathSciNet  Article  MATH  Google Scholar 

  14. Duarte, L. D. V., Wicht, J. & Gastine, T. Physical conditions for Jupiter-like dynamo models. Icarus 299, 206–221 (2018).

    ADS  Article  CAS  Google Scholar 

  15. Grote, E. & Busse, F. H. Hemispherical dynamos generated by convection in rotating spherical shells. Phys. Rev. E 62, 4457–4460 (2000).

    ADS  Article  CAS  Google Scholar 

  16. Salpeter, E. E. On convection and gravitational layering in Jupiter and in stars of low mass. Astrophys. J. 181, L83–L86 (1973).

    ADS  Article  CAS  Google Scholar 

  17. Stevenson, D. J. Reducing the non-axisymmetry of a planetary dynamo and an application to Saturn. Geophys. Astrophys. Fluid Dyn. 21, 113–127 (1982).

    ADS  Article  Google Scholar 

  18. Stanley, S. & Mohammadi, A. Effects of an outer thin stably stratified layer on planetary dynamos. Phys. Earth Planet. Inter. 168, 179–190 (2008).

    ADS  Article  Google Scholar 

  19. Dietrich, W. & Jones, C. A. Anelastic spherical dynamos with radially variable electrical conductivity. Icarus 305, 15–32 (2018).

    ADS  Article  Google Scholar 

  20. Glatzmaier, G. A. Computer simulations of Jupiter’s deep internal dynamics help interpret what Juno sees. Proc. Natl Acad. Sci. USA 115, 6896–6904 (2018).

    ADS  Article  PubMed  Google Scholar 

  21. Stevenson, D. J. Cosmochemistry and structure of the giant planets and their satellites. Icarus 62, 4–15 (1985).

    ADS  Article  CAS  Google Scholar 

  22. Wilson, H. F. & Militzer, B. Rocky core solubility in Jupiter and giant exoplanets. Phys. Rev. Lett. 108, 111101 (2012).

    ADS  Article  PubMed  CAS  Google Scholar 

  23. Wilson, H. F. & Militzer, B. Solubility of water ice in metallic hydrogen: consequences for core erosion in gas giant planets. Astrophys. J. 745, 54 (2012).

    ADS  Article  CAS  Google Scholar 

  24. Wahl, S. M., Wilson, H. F. & Militzer, B. Solubility of iron in metallic hydrogen and stability of dense cores in giant planets. Astrophys. J. 773, 95 (2013).

    ADS  Article  CAS  Google Scholar 

  25. González-Cataldo, F., Wilson, H. F. & Militzer, B. Ab initio free energy calculations of the solubility of silica in metallic hydrogen and application to giant planet cores. Astrophys. J. 787, 79 (2014).

    ADS  Article  CAS  Google Scholar 

  26. Helled, R. & Stevenson, D. The fuzziness of giant planets’ cores. Astrophys. J. Lett. 840, L4 (2017).

    ADS  Article  CAS  Google Scholar 

  27. Vazan, A., Helled, R. & Guillot, T. Jupiter’s evolution with primordial composition gradients. Astron. Astrophys. 610, L14 (2018).

    ADS  Article  Google Scholar 

  28. Wahl, S. M. et al. Comparing Jupiter interior structure models to Juno gravity measurements and the role of a dilute core. Geophys. Res. Lett. 44, 4649–4659 (2017).

    ADS  Article  Google Scholar 

  29. Stanley, S. & Bloxham, J. Numerical dynamo models of Uranus’ and Neptune’s magnetic fields. Icarus 184, 556–572 (2006).

    ADS  Article  Google Scholar 

  30. Bolton, S. J. et al. The Juno mission. Space Sci. Rev. 213, 5–37 (2017).

    ADS  Article  Google Scholar 

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Acknowledgements

All authors acknowledge support from the Juno project. K.M.M. is supported by the US Department of Defense (DoD) through the National Defense Science and Engineering Graduate Fellowship (NDSEG) programme and L.K. through a US National Science Foundation Graduate Fellowship.

Reviewer information

Nature thanks C. Jones and the other anonymous reviewer(s) for their contribution to the peer review of this work.

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Authors and Affiliations

Authors

Contributions

K.M.M. and J.B. wrote the manuscript and performed the data analysis. K.M.M., J.B., J.E.P.C., S.K., J.L.J. and J.M.G.M. contributed to discussions of the data analysis, and K.M.M., R.K.Y., L.K., H.C., J.B. and D.J.S. contributed to discussions of the dynamo implications. All authors contributed to editing and revising the manuscript. J.E.P.C. is principal investigator of the Juno magnetometer investigation, S.J.B. is principal investigator of the mission and S.M.L. is project scientist of the mission.

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Correspondence to Jeremy Bloxham.

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Moore, K.M., Yadav, R.K., Kulowski, L. et al. A complex dynamo inferred from the hemispheric dichotomy of Jupiter’s magnetic field. Nature 561, 76–78 (2018). https://doi.org/10.1038/s41586-018-0468-5

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  • DOI: https://doi.org/10.1038/s41586-018-0468-5

Keywords

  • Jupiter
  • Juno Orbit
  • Dynamo Region
  • Spherical Harmonic Reference Model
  • Field Morphology

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