Millinetwon force produced by plasma interactions with atmospheric pressure inert gas in a micrometer thruster under the effect of an external electric field is investigated using a two dimensional self consistent plasma-fluid model. The resulted thrust can be used to control small spacecrafts at the Lower Earth Orbit (LEO). The thruster's dimensions are 0.4 mm (width) × 0.2 mm (height) and composed of two opposite plates (a cathode and an anode) with a dielectric material in between. The cathode length is 0.4 mm and it exists below the dielectric material of the same length and of a height of 20 μm. The anode of 30 μm length exists at the top of the dielectric. The inert gas directly interacts with both of the anode and the dielectric material with Laminar gas flow considered. Plasma starts at the anode dielectric boundary and an ion sheath starts to develop after about 10−8 s. The sheath propagates towards the low potential dielectric material and ions are generated by secondary emission accumulate on the dielectric surface extending the anode virtual length. Individual charged species number density in the discharge is calculated by solving species continuity equations with gas energy and momentum equations. The conservation equations for electrons, ions, and metastables are solved concurrently with the Poisson equation. Gas parameters are calculated including temperature, pressure and gas depletions. The effect of changing current and potential difference on the gas parameters is investigated. Electrons' temperature is calculated. The force produced by the ion sheath is calculated for different gas parameters.
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