Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, that a substantial number of fusion reactions occur.; In this thesis we examine the propagation of a beam through vapor densities of {dollar}{lcub}sim{rcub}10sp{lcub}14{rcub}{dollar} to {dollar}10sp{lcub}15{rcub}{dollar} molecules per {dollar}cmsp3{dollar} of both lithium and Flibe, a molten salt mixture of LiF and {dollar}BeFsb2.{dollar} The focal spot radius of the beam is expected to be strongly influenced by collisions of the beam ions with the background gas. The predominant collision processes are beam stripping, where the charge state of the beam ions increases due to the loss of electrons, and ionization of the background gas. These processes can significantly alter and amplify the electrodynamic interaction of the beam ions with the collective electromagnetic field of the combined beam-plasma system.; The collisions of the beam ions with the background gas result in a highly random distribution of beam charge states and complicated plasma phenomena, making analytic methods inadequate for qualitatively describing the dynamics of the beam. We have therefore developed a new computer code, BTRAC, consisting of a fully electromagnetic 2{dollar}{lcub}1over2{rcub}{dollar}D particle-in-cell (PIC) simulation coupled to a Monte Carlo collision (MCC) model. The PIC code simulates the complete dynamics of the interaction of the various charged particle species: beam ions, electrons and background gas ions, with the self-generated fields; while the MCC code follows the collisions between the beam ions and the background gas atoms. (Abstract shortened by UMI.)...