At Saturn, the
magnetosphere separates more readily into decoupled inner and outer
regions. In the outer part, the material and energy budgets of the the Titan-
magnetosphere interaction have yet to be worked out in full detail,
In the inner magnetosphere, the main objective is to
determine the structure, composition and source regions of the ambient
plasma.The recent
Hubble observation of a dense cloud of hydroxl, OH, in the
Tethys region and near the rings has
introduced a
totally new element into inner magnetosphere physics. It will be necessary
to reanalyze the
composition
questions of the inner magnetosphere in order to integrate this finding
into a coherent picture. A totally new paradigm of magnetosphere plasma
physics, different from that which has worked so well at Earth and Jupiter,
will have to be devised. At Earth and Jupiter, the processes typical of
fully ionized plasmas are the fastest and the plasma can be treated as
such. At Saturn and apparently at Neptune, the interactions between the
plasma and the neutral gas is dominant and the physics will be similar to
that of a planetary ionosphere, namely, dominated by the neutral component.