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Hammond et al. 1990
Hammond, C.M., Walker, R.J. and Kivelson, M.G. (1990). A Pincer-shaped plasma sheet at Uranus. Journal of Geophysical Research 95: doi: 10.1029/90JA00696. issn: 0148-0227.

A model from Voigt et al. (1987) and an MHD simulation from Walker et al. (1989) both show that the curvature of the plasma sheet at Uranus changes as the dipole tilt varies between 38¿ and 22¿. The models suggest that one of the two partial traversals of the uranian plasma sheet made during the outbound trajectory of Voyager 2 can be explained as an entry into the highly curved plasma sheet that develops when Uranus is near the maximum dipole tilt value of 38¿; previously both partial traversals have been explained as anomalous. The spacecraft would have reversed its motion relative to the plasma sheet as the continued rotation diminished the dipole tilt and the retreating plasma sheet uncurled. As the dipole tilt approached its minimum value, spacecraft motion towards the neutral sheet resumed and the traversal of the plasma sheet was completed. Evidence from the PWS plasma wave detector suggests that the spacecraft trajectory skimmed the plasma sheet boundary layer for several hours prior to the partial immersion. The plasma sheet of the Voigt et al. model; near maximum dipole tilt, the plasma sheet is pincer-shaped. The unusual geometry implies that Voyager 2 remained near the plasma sheet boundary layer during the period suggested by the PWS data. Thus the simulation accounts easily for the first of the plasma sheet encounters previously called anomalous. The second partial immersion remains anomalous, having previously been related to substorm activity, and thus is not discussed here. The stagnation distances of the earth and Uranus at the nose of the magnetopause were used to scale the Walker et al. (1989) simulation of the terrestrial magnetosphere to represent the uranian magnetospehre. The rescaled model was found to predict the radial extent of the magnetotail of Uranus remarkably well. Previous studies which have suggested that the uranian magnetotail is blunter than that of the earth have not compared tail widths at an appropriately scaled distance down the tail. ¿ American Geophysical Union 1990

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Abstract

Keywords
Magnetospheric Physics, Plasma sheet, Magnetospheric Physics, Planetary magnetospheres
Journal
Journal of Geophysical Research
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Publisher
American Geophysical Union
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