Numerical Simulation of RotationDriven Plasma Transport In the Jovian Magnetosphere
Abstract
A Jupiter version of the Rice Convection Model (RCMJ) was developed with support of an earlier NASA SR&T grant. The conversion from Earth to Jupiter included adding currents driven by centrifugal force, reversing the planetary magnetic field, and rescaling various parameters. A series of informative runs was carried out, all of them solving initial value problems. The simulations followed an initial plasma torus configuration as it fell apart by interchange instability. Some conclusions from the simulations were the following: 1. We confirmed that, for conventional values of the torus density and ionospheric conductance, the torus disintegrates by interchange instability on a time scale of approx. one day, which is 12 orders of magnitude shorter than the best estimates of the average residence time of plasma in the torus. 2. In the model, the instability could be slowed to an arbitrary degree by the addition of sufficient impounding energetic particles, as suggested earlier by Siscoe et al (1981). However, the observed energetic particles do not seem sufficient to guarantee impoundment (e.g., Mauk et al., 1996). 3. Whether inhibited by impoundment or not, the interchange was found to proceed by the formation of long fingers, which get thinner as they get longer. This picture differed dramatically from the conventional radialdiffusion picture (e.g., Siscoe and Summers (1981)), more superficially with the outwardmovingblob picture (Pontius and Hill, 1989). The obvious limitation of the original RCMJ was that it could not represent a plasma source. We could represent the decay of a preexisting torus, but we could not represent the way ionization of material from Io continually replenishes the plasma. We consequently were precluded from studying a whole set of fundamental issues of torus theory, including whether the system can come to a steady state.
 Publication:

National Aeronautics and Space Administration Report
 Pub Date:
 January 1997
 Bibcode:
 1997nasa.reptY....W
 Keywords:

 Numerical Analysis;
 Plasmas (Physics);
 Centrifugal Force;
 Magnetospheres;
 Models;
 Images;
 Toruses;
 Toroidal Plasmas;
 Steady State;
 Solvents;
 Simulation;
 Boundary Value Problems;
 Convection;
 Energetic Particles;
 Ionization;
 Jupiter (Planet);
 Lunar and Planetary Exploration