Traveling-wave induction launchers

An analysis of traveling-wave induction launchers shows that induction is a feasible method of producing armature current and that efficient accelerators can be built without sliding contacts or arcs. In a traveling-wave induction launcher the armature current is induced by a slip speed between the armature and a traveling magnetic field. At 9-m/s slip speed a 9-kg projectile with an aluminum armature weighing 25% of the total mass can be accelerated to 3000 m/s in a 5-m-long barrel with a total ohmic loss in the barrel coils and armature of 4% of the launch kinetic energy and with an average armature temperature rise of 220°C, but a peak excitation frequency of 8600 Hz is required. With a 2-kg launch mass the ohmic loss is 7%. A launcher system optimized for rotating generators would have a peak frequency of 4850 Hz; with an aluminum armature weighing 33% of the launch mass and a slip speed of 30 m/s the total ohmic loss in the generators, cables, and accelerator would be 43% of the launch kinetic energy, and the average armature temperature rise would be 510°C