Life-limiting Trends of High-Specific Impulse Ion Optics

The sensitivity of high-specific impulse ion optics throughput to thruster operating condition and ion optics geometry is presented. A two-dimensional ion optics code is used to predict the location, energy, and current of charge exchange ions that impact the accelerator electrode. The throughput capability of ion optics is shown to be limited by the transition of the erosion from aperture enlargement to electrode thinning at high current densities. For lower current densities, trends are discussed relating throughput capability to aperture geometry.