Study of multi-electron ionization and charge exchange in HIBF

Beam ion stripping on background gases or plasma in a Heavy Ion Beam Fusion (HIBF) chamber increases the charge state of the beam and the diameter of the focus, complicating the final focusing on the focusing target. To model beam transport in the chamber, it is necessary to know the beam charge-state evolution, including both ionization and charge exchange dynamics.; The main objective of this research is to explore theoretical approaches including scaling law. Improved models are developed to calculate multi-electron loss, especially ion stripping and charge exchange cross sections, for both near-term experiments and future power plant scale HIBF research.; First, a new space-charge neutralization approach that uses electron injection is proposed for the ion beam transport in HIBF chamber. An analytical study was performed to illustrate the plasma dynamics and final neutralization effects with this technique. The results examine the effect of different injected electron profiles.; Next, to improve the accuracy of such simulations, methods to improve cross sections of ionization and charge exchange are studied. Both classical and quantum mechanical approaches are examined. Attention is focused on the interaction by low-charge-state heavy ions. Multi-electron processes for dressed ions, including screening and anti-screening effects, internuclear forces, are given special attention, This analysis is complex and requires a combining several different theoretical approaches. Finally, a Classic Trajectory Monte Carlo (CTMC) model based on an improvement of Olson's n-body CTMC method is presented. This model solves the n-body ion-atom ionization problem in a regime of intent to HIBF. In the paper, a new and complete computational module for these interactions has been developed. The cross section data for Xe, Cs, and Bi ions colliding with various background gases (Xe, N2, Ar and Flibe) is presented. After the calculation of the cross section data, the predicted energy dependence of the beam ion and background gas target is analyzed and scaling laws are developed to give a larger range of energies. Due to the scarcity of prior experimental and theoretical data, comparisons between the calculated data and prior data is limited to selected cases, The cross section data is being implemented into the Large Scale Plasmas (LSP) code package, a beam transport code that is widely used for HIBF studies. This improved LSP package can be used to study the effects of ionization on neutralized drift compression and focusing in HIBF. This code package studied will provide further physical insight into current neutralized transport experiments, and future HIBF studies.; In addition to the study of atomic effects for HIBF, plasma dynamics in a low-energy radio frequency (RF) discharge is studied through the implementation of a new Monte Carlo Collision (MCC) module developed for including into a Particle-In-Cell (PIC) package, The MCC module uses available cross section data for the light ion-atom collisions as the input. The results illustrate the collision effects on particle transport in the discharge.