A study of Uranian magnetospheric convection
Abstract
In order to understand and explain the low-energy plasma structures observed by the PLS experiment on Voyager 2 in the Uranian inner magnetosphere, an analytic and self-consistent model of a time-dependent solar-wind driven convection system at Uranus has been developed in the corotating coordinate system. Many important results of this model agree with the observations very well.
Because of the unusual orientation of the planetary rotation and magnetic dipole axes, magnetic merging on the dayside magnetopause varies as a function of planetary spin, in response to the changing orientation of the planetary magnetic field relative to the upstream interplanetary magnetic field, which is assumed to have a fixed direction for many planetary rotations. Therefore the magnitude of the solar-wind driven convection electric field varies sinusoidally in time with the 17.2 hr planetary spin period, even though the field direction is fixed in the corotating frame in a direction analogous to the dawn-to-dusk direction in the Earth's magnetosphere.
By assuming conservation of the first adiabatic invariant we find that the "hot" (few keV) protons observed by the PLS experiment in the inner magnetosphere may be convected Sunward from a pick-up source provided by electron impact ionization of the neutral torus of the outermost satellite Oberon. Under the time-dependent convection field this hot plasma forms a ring-current shielding layer in the region L = 5
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Citation
Ye, Gang. "A study of Uranian magnetospheric convection." (1990) Diss., Rice University. https://hdl.handle.net/1911/16410.