Planetary Magnetism

Connerney, J. E. P.

doi:10.1016/b978-044452748-6.00159-0

Cited by 23 publications

(19 citation statements)

References 208 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have demonstrated that in the equatorial zone, the low‐altitude magnetic field estimated from the loss cone size exceeds the model magnetic field, up to a factor of ~2, which is in agreement with direct magnetic field measurements [ Bolton et al , ]. Although only results from the VIP4 model have been shown here, the same conclusion can be derived from VIT4 [ Connerney , ] and VIPAL [ Hess et al , ] models, which predict similar loss cone sizes as the VIP4 model. For high‐latitude measurements (in the northern hemisphere), on the other hand, we did not find any reliable difference between the model loss cone size and the loss cone estimated from plasma data, which indicates no significant magnetic field anomaly at higher latitudes for this particular longitudinal pass.…”

Section: Discussionsupporting

confidence: 87%

See 1 more Smart Citation

Searching for low‐altitude magnetic field anomalies by using observations of the energetic particle loss cone on JUNO

Zhang

Thorne

et al. 2017

Geophysical Research Letters

View full text Add to dashboard Cite

In inner planetary magnetospheres, pitch angle distributions of charged particles are shaped by the global magnetic field topology when they bounce fast along magnetic field lines. Therefore, one can estimate the magnetic field intensity at the top of the atmosphere from the loss cone size, inferred from particle pitch angle distributions at higher altitudes. We propose such a technique to estimate the magnetic field intensity near the top of Jovian atmosphere based on Jupiter Energetic Particle Detector Instruments particle distributions captured by JUNO and verify the algorithm by using plasma measurements from Van Allen Probes in the Earth's inner magnetosphere. Our results demonstrate that the low‐altitude magnetic field can be significantly larger than the expected field from present models, which supports recent reports on the anomaly of Jovian internal magnetic field from in situ JUNO measurements. We also discuss possible modifications and applications of the proposed technique to future investigations of the global Jovian magnetic field configuration.

show abstract

Section: Discussionsupporting

confidence: 87%

“…Such models can be improved by using additional constraints from aurora emission measurements. For instance, the region of the localized auroral emission associated with Io should be conjugated along the magnetic field line to the known location of Io's orbit [Connerney et al, 1998;Connerney, 2007;Hess et al, 2011].…”

Section: Introductionmentioning

confidence: 99%

Searching for low‐altitude magnetic field anomalies by using observations of the energetic particle loss cone on JUNO

Zhang

Thorne

et al. 2017

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…3. (a and b) A comparison of the magnetic energy spectra per spherical harmonic degree and order m for the three different Jupiter field models VIP4 [Connerney et al, 1998], VIT4 [Connerney, 2007], and Ridley [Ridley, 2012] with the time-averaged spectrum of the numerical simulation. The thick black lines in Figure 3a illustrate the predicted noise level for the Juno magnetometer.…”

Section: Gastine Et Almentioning

confidence: 99%

“…Spacecraft data allow to model the Jovian magnetic field up to spherical harmonic degree and order of 4-5 [Connerney et al, 1998;Connerney, 2007;Hess et al, 2011]. The observations reveal that the Jovian magnetic field is dominated by a tilted dipole with an Earth-like inclination angle around 10 • and is about an order of magnitude stronger than the geomagnetic field.…”

Section: Introductionmentioning

confidence: 99%

Explaining Jupiter's magnetic field and equatorial jet dynamics

Gastine

Wicht

Duarte

et al. 2014

Geophysical Research Letters

117

View full text Add to dashboard Cite

Spacecraft data reveal a very Earth-like Jovian magnetic field. This is surprising since numerical simulations have shown that the vastly different interiors of terrestrial and gas planets can strongly affect the internal dynamo process. Here we present the first numerical dynamo that manages to match the structure and strength of the observed magnetic field by embracing the newest models for Jupiter's interior. Simulated dynamo action primarily occurs in the deep high electrical conductivity region while zonal flows are dynamically constrained to a strong equatorial jet in the outer envelope of low conductivity. Our model reproduces the structure and strength of the observed global magnetic field and predicts that secondary dynamo action associated to the equatorial jet produces banded magnetic features likely observable by the Juno mission. Secular variation in our model scales to about 2000 nT per year and should also be observable during the one year nominal mission duration.Comment: 7 pages, 4 figures, accepted for publication in Geophysical Research Letter

show abstract

“…[4] Many studies of the magnetic mapping of Io to the planet and its comparison with the positions of Io's footprints observed in UV and Infrared have been performed [Connerney et al, 1998;Grodent et al, 2008a;Bonfond et al, 2009], which have led to the determination of new internal magnetic field models [Connerney et al, 1998;Connerney, 2007;Grodent et al, 2008a]. However, none of these models allowed a correct longitudinal mapping of the Io footprints: Studies by Bonfond et al [2009] in the UV and by Hess et al [2010a] in radio showed a large (up to 10°) longitude difference between the predicted and observed positions of the Io footprints.…”

Section: Introductionmentioning

confidence: 99%

Model of the Jovian magnetic field topology constrained by the Io auroral emissions

et al. 2011

View full text Add to dashboard Cite

[1] The determination of the internal magnetic field of Jupiter has been the object of many studies and publications. These models have been computed from the Pioneer, Voyager, and Ulysses measurements. Some models also use the position of the Io footprints as a constraint: the magnetic field lines mapping to the footprints must have their origins along Io's orbit. The use of this latter constraint to determine the internal magnetic field models greatly improved the modeling of the auroral emissions, in particular the radio ones, which strongly depends on the magnetic field geometry. This constraint is, however, not sufficient for allowing a completely accurate modeling. The fact that the footprint field line should map to a longitude close to Io's was not used, so that the azimuthal component of the magnetic field could not be precisely constrained. Moreover, a recent study showed the presence of a magnetic anomaly in the northern hemisphere, which has never been included in any spherical harmonic decomposition of the internal magnetic field. We compute a decomposition of the Jovian internal magnetic field into spherical harmonics, which allows for a more accurate mapping of the magnetic field lines crossing Io, Europa, and Ganymede orbits to the satellite footprints observed in UV. This model, named VIPAL, is mostly constrained by the Io footprint positions, including the longitudinal constraint, and normalized by the Voyager and Pioneer magnetic field measurements. We show that the surface magnetic fields predicted by our model are more consistent with the observed frequencies of the Jovian radio emissions than those predicted by previous models.

show abstract

Planetary Magnetism

Cited by 23 publications

References 208 publications

Searching for low‐altitude magnetic field anomalies by using observations of the energetic particle loss cone on JUNO

Searching for low‐altitude magnetic field anomalies by using observations of the energetic particle loss cone on JUNO

Explaining Jupiter's magnetic field and equatorial jet dynamics

Model of the Jovian magnetic field topology constrained by the Io auroral emissions

Contact Info

Product

Resources

About