Other
Scientific paper
Jan 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995phdt........20h&link_type=abstract
Thesis (PH.D.)--HARVARD UNIVERSITY, 1995.Source: Dissertation Abstracts International, Volume: 56-12, Section: B, page: 6635.
Other
1
Scientific paper
We present new models of the magnetic fields of Uranus and Neptune, based on data provided by the Voyager II magnetic field experiment. We find the simplest models that satisfy the data, and use the observed surface heat flow as a constraint on the magnetic field structure. Our models are similar to those previously described far from the planets, but resolve smaller scale structure close to the planets' surfaces. The field of Neptune is much better constrained than that of Uranus, and the field in the northern hemisphere of Neptune is much better constrained than that in the southern hemisphere. Using extremal models, we show that the large dipole tilts and non-dipole dominance of the fields are robust features required by the data, but that the data do not require the field to have strong symmetry about any axis. We examine the consequences of the observed field and the limited electrical conductivity of the planetary interiors. Scaling analysis suggests that the toroidal field required for magnetospheric balance in the dynamo region is too strong to be consistent with the observed surface heat flow. The dynamos of Uranus and Neptune would then be in the weak field regime. We suggest that the lack of magnetostrophic balance may account for the radically different field morphologies of Uranus and Neptune compared with the Earth, Jupiter and Saturn. Using a kinematic dynamo similar to the Kumar -Roberts dynamo, we explore the generation of fields dominated by the equatorial dipole field, rather than the axial dipole. We find a wide range of flows which preferentially generate such fields, including many which give steady solutions. Of particular interest is a flow which lacks toroidal motion. Differential rotation is less significant in the new flows than in flows which lead to a dominant axial dipole. Various mechanisms have been suggested to account for the anomalous field morphology of Uranus and Neptune. While several of these mechanisms seem promising, in particular our suggestion of a weak-field state, we conclude that understanding of the detailed dynamical process is insufficient to draw firm conclusions, as is also the case for other planetary and stellar magnetic fields.
No associations
LandOfFree
The Magnetic Fields of Uranus and Neptune. does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Magnetic Fields of Uranus and Neptune., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Magnetic Fields of Uranus and Neptune. will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-837715