PBFA II ion diode theory and implications

Fully electromagnetic, relativistic, two-dimensional, particle-in-cell (PIC) simulations of barrel-type and extractor-type Applied-B ion diodes have increased confidence in the design of present and future diodes for the Particle Beam Fusion Accelerator II (PBFA II). In addition, the data from various experiments on Proto I, Proto II, and PBFA I Applied-B ion diodes are inconsistent with previous models of diode operation, based on anode-cathode gap closure from expanding plasmas. A new model has been devised and applied to the PBFA II diode to explain the diode impedance and its time history, and to suggest methods for controlling the impedance. (author)