Studies of applications of inertial confinement fusion motivated the development of a plasma model composed of

  1. perfectly conducting fluid
  2. relatively energetic ions not in thermal equilibrium with the fluid
  3. an electromagnetic field.
The fluid is modeled as a continuum, but the trajectories of the ions are determined from integration of the equations of motion for a statistically representative sample of simulation particles because the ion ranges in the fluid are comparable to characteristic dimensions of containment vessels. The model constituents interact electrodynamically, collisionally, and through ionization and recombination processes. The model of the collisional interaction is based on the stopping power of the fluid; it leads to technical difficulties because of the widely different characteristic lengths associated with collisional interactions and with macroscopic fluid phenomena. These difficulties are resolved with a specially constructed elementary one-dimensional model of the collisional interaction. The finite difference equations describing the evolution of the complete ion-plasma system are integrated numerically for an isotropic ion source located on the cylinder axis. The solutions indicate different ion behavior for low- and highfluid densities. The ions expand as a diffuse cloud through low-density fluids, but aggregate into perpendicular-to-the-magnetic-field sheets in high-density fluids; the discovery of these strikingly different behaviors constitutes the main contribution of this work.