Development of Metallic Ion Thruster using Magnetron Electron-beam Bombardment

Abstract

The electric thruster is a device that uses electromagnetic fields to control and accelerate ions An ion thruster using a metallic target as the propellant has been developed Different from the inert gas used in conventional plasma thrusters the metallic target is in the solid state high density easy to be stored and cheap The design is divided into three parts: a metallic evaporator and an ion accelerator and a neutralizer The principle of electron-beam (E-beam) evaporation where a metal target is evaporated and ionized by thermal-emitted electrons is used The working condition is independent of the vacuum condition so that it works in the ultra-high vacuum space A focusing magnet with a magnetic field about 0 2~0 3 T between the target surface and the filament is used to guide electrons toward the center of the target so that the metal is evaporated and ionized A prototype has been built and tested The metallic targets were heated to more than 415 °C by electron bombardment A mass flow rate of (2 2±0 4)E-4 (g/s) and (1 8±0 3)E-5 (g/s) using Zn at 5 kV/3 mA and 1 kV/ 15mA E-beam current was measured An ionization rate of 0 03±0 01 % and 1 1±0 3 % using Zn at 5 kV and 1 kV E-beam current was measured Therefore the estimated thrust is 9 0±1 0 μN and 10 3±0 7 μN with a power of about 25 W The Estimated Isp is 12 300 s and 5 500 s respectively Considering the contribution of vapors the total thrust is 99±40 μN and 17 3±4 0 μN respectively

Date of Award	2019
Original language	English
Supervisor	Po-Yu Chang (Supervisor)