Research on electric field and electric breakdown problems of a micro-colloid thruster

Electrodes are key components of a micro-colloid thruster. There are two unavoidable problems in the designing of electrodes of a micro-colloid thruster. Firstly, the electric field must be high enough to induce the propellant to form a droplet and then burst. Secondly the problem of electric breakdown between two electrodes of a micro-colloid thruster should be paid special attention to when high potential is applied between electrodes. This paper presents an equation to predict the minimum electric field value to start an electrospray, which is based on the balance between the surface tension and the electrostatic field force on the surface of a droplet at the tip of the source emitter of a micro-colloid thruster. Finite element analysis (FEA) results show that, this minimum value of electric field, about 10 7 V/m can be archived when 3000 V is applied between electrodes. Experiments conducted on the home-made micro electrodes verifies that electric