On the Cone-Shaped Geometrical Design and Scale-Up of A Solenoid Thruster

This study continues from our previous research on the force created by coils with varying cross-sectional areas in the geomagnetic field. Realizing the potential effectiveness and force enhancement of small thrusters as a result of magnetic moment gradients, the study explores further advancement with enlarged scales, increasing current intensity, and adjustments for the size and geometry. To validate and assist theoretical predictions, commercial simulation software (COMSOL-Multiphysics) was adopted to simulate the experimental results at different scales. The simulations and experiments validated the theoretical predictions of coil forces in the geomagnetic field, expanding our understanding of the magnitudes of predicted force. The experimental tests utilized a cone-shaped geometry with noticeable variations in cross-sectional area, which yielded a measurement of millinewton-level thrust. However, with insertion of an iron core into the solenoid, the theoretical predictions of force magnitude showed deviations and necessitated corrections, revealing a reduction in the force due to mutual influences between the iron core material and the background magnetic field. Despite the corrections, the study has shown the importance of considering material properties and geometric characteristics for accurate force predictions, especially for conical shapes. The findings enhance our realization of thruster performance and the effects of cone-shaped designs on thrust. Through a comprehensive analysis of the experimental and simulation results, the research further reveals the potential and applicable range of the thruster, providing more information for future propulsion technology along this line. Based on the geomagnetic field, the magnetically propelled coil thruster is highlighted for its sustainability, resource efficiency, compact size, stable thrust, and environmental friendliness. Although much more development is needed to achieve a realistic implementation, the ultimate goal may provide an alternative propulsion system that emerges as an efficient and sustainable option for space missions with a minimum need for propellant and fuel.