Beam and deposition stability in light-ion fusion targets

This report is a quantitative review of the plasma stability of beam-target and deposition processes in parameter regimes appropriate to light ion driven inertial confinement fusion targets. The emphasis is on electrostatic and electromagnetic streaming instabilities driven by a charge and current neutralized ion beam. The analysis is conducted under the assumptions that the beam is collisionless and that the target medium is homogeneous and infinite in extent. In the ranges of parameters relevant to the beam and target (1 to 100 TW/cm2 power intensity, 4 MeV protons or appropriately scaled voltage for other light ions, solid to one percent solid density of target material, and plasma temperatures between 10 and 1000 eV), none of the streaming instabilities possesses a sufficiently large growth rate to be of concern. Also included is a section devoted to the discussion of two thermal instabilities: a potentially unstable interaction involving ion beam range shortening as the target temperature increases, and fluid condensation instability. Although no conclusive results regarding the condensation instability in light ion fusion targets are yet available, the range shortening interaction is found to be a stable process