Metallic Ion Thruster using Magnetron E-Beam bombardment

Kuo-Yi Chen^1*, Po-Yu Chang¹

¹institute of Space and Plasma Science, National Cheng Kung University, 台南市, Taiwan

* Presenter:Kuo-Yi Chen, email:aaaa8444@gmail.com

Electric thruster is a device that uses electromagnetic fields to control and accelerate ions. An ion thruster using a metal target as the propellant is being built. Different from inert gas used in conventional plasma thrusters, the metal target is in solid state, high density, easy to be stored and cheap. The design is divided into three parts: metal evaporator and ion accelerator and neutralizer. The principle of E-beam evaporation, where metal target is evaporated and ionized by thermal emission electrons, is used. The working condition is independent to the vacuum condition so that it also works in the ultra-high vacuum space. A focus magnet with a magnetic field about 0.3~0.35T between the target surface and the filament, is used to guide electrons so that the metal is evaporated and ionized. A prototype has been built and is under testing. Metal targets were heated to more than 230 °C by electrons bombardment. A mass flow rate of 8.0±1.3μg/sec using Zn was measured. Therefore, the estimated thrust is β*1mN with a power of 630W assuming 5kV accelerating voltage is used. The parameter β is the ionization rate of the metal vapor and will be measured experimentally. The thrust is much larger than those provided from existing thrusters with similar powers to date. The project is supported by Ministry of Science and Technology (MOST) project under Award Number 107-2628-E-006-006-MY2.

Keywords: Elactric Thrust, Electron-beam evaporation, Solid propellant