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

Moore, Kimberly M. and Yadav, Rakesh K. and Kulowski, Laura and Cao, Hao and Bloxham, Jeremy and Connerney, John E. P. and Kotsiaros, Stavros and Jørgensen, John L. and Merayo, Jóse M. G. and Stevenson, David J. and Bolton, Scott J. and Levin, Steven M. (2018) A complex dynamo inferred from the hemispheric dichotomy of Jupiter’s magnetic field. Nature, 561 (7721). pp. 76-78. ISSN 0028-0836. doi:10.1038/s41586-018-0468-5.

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The Juno spacecraft, which is in a polar orbit around Jupiter, is providing direct measurements of the planet’s magnetic field close to its surface. 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) 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.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access
Moore, Kimberly M.0000-0003-3162-437X
Yadav, Rakesh K.0000-0002-9569-2438
Cao, Hao0000-0002-6917-8363
Bloxham, Jeremy0000-0001-8556-2675
Connerney, John E. P.0000-0001-7478-6462
Stevenson, David J.0000-0001-9432-7159
Bolton, Scott J.0000-0002-9115-0789
Levin, Steven M.0000-0003-2242-5459
Alternate Title:Hemispheric dichotomy of Jupiter's magnetic field indicative of a complex Jovian dynamo
Additional Information:© 2018 Springer Nature Limited. Received: 9 April 2018; Accepted: 26 July 2018; Published online 5 September 2018. 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. Author 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. The authors declare no competing interests. Data availability: The Juno magnetometer data used in this study will be made available through the NASA Planetary Data System ( in accordance with NASA policy. An animated version of Fig. 2 is available at
Group:Astronomy Department
Funding AgencyGrant Number
National Defense Science and Engineering Graduate (NDSEG) FellowshipUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
Issue or Number:7721
Record Number:CaltechAUTHORS:20180717-143926250
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87934
Deposited By: George Porter
Deposited On:06 Sep 2018 16:55
Last Modified:16 Nov 2021 00:22

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