Numerical study of ion mode saturation in applied-B ion diodes

Summary form only given. The authors have begun a study of ion mode saturation using the 3-D particle-in-cell code QUICKSILVER with the primary aim of understanding the physical mechanisms governing the ion mode saturation in applied-B ion diodes. The practical objective is to discover under what conditions the ion mode will saturate at acceptably low amplitudes. Particular attention is given to the scaling with respect to various diode configuration parameters such as the insulating magnetic field strength, the anode-cathode gap, the anode emission height, and the ion current enhancement over the Child-Langmuir current. Long time scale simulations have also been performed which demonstrate the potential for cycle behavior in the ion mode amplitude. A comparison of the results with experimental data from PBFA II has been made.