Abstract
A substantial improvement of propellant utilization efficiency can be achieved by reducing the
diameters of accelerator grid apertures by ion machining, in which the accelerator grid hole geometries were defined self-consistently. In this paper, a fast ion machining calculation method is proposed, which can be used to design a high performance ion thruster accelerator grid with small computation time. Calculation results using this method were compared with the ion machined accelerator grid apertures of the μ20 ion thruster obtained by experiments and ordinary time-marching simulations using the JIEDI tool. The comparisons showed that this method is very fast and successfully gave the accelerator grid hole geometries that provide higher propellant utilization efficiency than the conventional method. This method was also applied to the design of the grid hole geometries of an on/off ion thruster. The ion-machined accel grid successfully reduces ion leak during the extraction-off period than the ordinary straight hole grid.
