Patent attributes
An arcing protection circuit for the screen and accelerator grids of an ion thruster engine includes an impedance, which in one embodiment, is fixed, and in another, is variable, coupled in series between the accelerator grid of the engine and a current return path of the grid in such a way that an increase in accelerator grid current resulting from a plasma arc occurring between the screen grid and the accelerator grid is converted by the impedance into a rapid reduction in the voltage difference between the screen and accelerator grids, thereby extinguishing the arc. The arcing protection circuit also includes a monitoring circuit coupled to the accelerator grid that senses an increase in the voltage on the accelerator grid resulting from the plasma arc, and in response thereto, causes the accelerator grid power supply to reduce the voltage on the accelerator grid.
