Differential Rotation in Jupiter's Interior Revealed by Simultaneous Inversion for the Magnetic Field and Zonal Flux Velocity
Abstract
A key objective of the current Juno mission (Bolton et al., 2017, https://doi.org/10.1126/science.aal2108) is the direct determination of the secular variation (time dependency) of Jupiter's internal magnetic field in order to further understand the dynamics of Jupiter's interior. Here, we find that the residuals to a static, baseline model of the magnetic field are consistent with the effects of secular variation, specifically secular variation arising from zonal drift of the field. We present a technique for simultaneously inverting for the main magnetic field and secular variation due to zonal drift of the field. We explore the required drift systematically and argue that although the drift is dominated by a prograde super-rotation, corresponding to approximately 1 part in 106 relative to System IIIa (1965), there is also evidence for differential drift of the field. We compare the resultant secular variation with that determined by Moore et al. (2019, https://doi.org/10.1038/s41550-019-0772-5) and Connerney et al. (2022, https://doi.org/10.1029/2021je007055) and find good agreement. This suggests that the drift rate of Jupiter's magnetic field is steady over time periods of several decades, though short period secular variation (such as that resulting from torsional oscillations) superimposed on this steady secular variation is still possible.
Additional Information
© 2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Issue Online: 18 May 2022; Version of Record online: 18 May 2022; Accepted manuscript online: 10 May 2022; Manuscript accepted: 06 May 2022; Manuscript revised: 04 May 2022; Manuscript received: 19 November 2021. The authors acknowledge support from the NASA Juno Project. In addition, KMM is supported by a 51 Pegasi b Fellowship through the Heising-Simons Foundation. Data Availability Statement: All the Juno magnetometer data used in this study are available from the NASA Planetary Data System (Connerney, 2017). The models produced in this study, together with a Python script for reading them, are archived in the Harvard Dataverse (Bloxham, 2022).Attached Files
Accepted Version - JGR_Planets_-_2022_-_Bloxham_-_Differential_rotation_in_Jupiter_s_interior_revealed_by_simultaneous_inversion_for_the_acc.pdf
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Additional details
- Eprint ID
- 115184
- Resolver ID
- CaltechAUTHORS:20220616-665434600
- 51 Pegasi b Fellowship
- Heising-Simons Foundation
- Created
-
2022-06-21Created from EPrint's datestamp field
- Updated
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2022-06-21Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences