Analysis and Evaluation of Three-Stage Twisty Octapole Field Electromagnetic Launcher

In this paper, we propose an improved launch mode called multistage twisty multipole electromagnetic launcher. The twisty multipole magnetic field configuration is resolved, and the group power supply module is considered. The induced eddy current of the projectile is considered, and the analysis of electromagnetic force and torque has been performed. A full 3-D transient motion simulation with multiple degrees of freedom is carried on the three-stage twisty octapole field electromagnetic launcher. The simulation results indicate that the magnetic torque of rotational motion is impressively large and the transverse displacement of the projectile is much little. The torsion option of multistage pole coils makes little influence on axial acceleration force and exit velocity comparing with the appositional configuration. The theoretical analysis and numerical simulations indicate that the projectile is accelerated with spinning motion about its axis which could keep the projectile fly stability. We suggest this launch mode could be applied in the evacuated tube transportation vehicle.