Plasma Behavior in Magnetically Protected Inertial Confinement Fusion Reactor Cavities

Investigations of the feasibility of commercial inertial confinement fusion (ICF) reactors have led to studies of a variety of plasma regimes and behaviors. Presented in the paper are

1. a general discussion of phenomena inside ICF reactor vessels
2. parameter ranges of interest in practical applications
3. mathematical description of a new plasma model
4. representative results with discussions of their utility.

The plasma model developed for the study of phenomena inside ICF reactor cavities with magnetically protected walls is composed of three constituents:

1. ionized atoms in local thermodynamic equilibrium that are initially distributed uniformly throughout the region of interest and can be represented as a fluid
2. energetic ions whose range in the fluid constituent is equal to or greater than characteristic dimensions of the reactor vessel
3. electrons.

These constituents interact through electrodynamic and collisional forces and through ionization and/or recombination processes. The finite difference equations describing these interactions are solved numerically; the solutions represent time evolutions of conditions inside cylindrical reactor cavities following the production of energetic ions during the compression and burn of the deuterium-tritium fuel inside a small pellet. Debris plasma expansion occurs through an ionized low-density background fluid with an imbedded externally generated magnetic field. Results indicate that the background fluid has little effect on ion trajectories before the pressure waves reflect from the cavity walls; however, the ions impart such a high velocity to the background fluid that in spite of large energy deposition, the temperature and density in the region interior to the expanding ions decrease to very low values.