Coilgun Electromagnetic Piston

If the creation of high-density axial pulsed magnetic fields is possible due to magnetic flux displacers, then the creation of an electromagnetic piston, the winding of which is capable of operating at magnetic pressures of thousands of atmospheres, is associated with serious difficulties. Indeed, a century has passed since the publication of the first patents for coil-type electromagnetic accelerators, known as coilguns, but today one can observe only not very successful experiments using ferromagnetic projectiles, the magnetic pressure in which is limited by the saturation induction of steel. The article discusses a possible way to solve the problem by using 3D printing technology to create an iron-free coilgun electromagnetic piston. The piston housing made of electrically insulating material, such as ceramics, has inside a cylindrical spiral made of the same, but porous ceramics. This cavity is filled with ultra-pure aluminum. Cooled to helium temperatures, about 10K, pure aluminum becomes superconducting. The winding of the electromagnetic piston is connected through a sliding contact to a diode fixed on the body of the coilgun. The same contact short-circuits the winding of the electromagnetic piston when the piston starts to move. After pulsed excitation of the electromagnetic piston winding, the piston moves from the neutral position. The diode remains stationary on the body of the coilgun, and the winding is short-circuited by the sliding contact located on the piston. Coilguns create push and pull electromagnetic fields that accelerate the piston as it moves through the channel. The force from the piston to the projectile is transmitted by a pusher built into the piston housing. The piston can be used repeatedly. A possible design of a piston and coils with coilgun magnetic flux concentrators for a 10-kilogram projectile with a diameter of 80 mm, accelerated to 4 km/s, is shown. The considered designs are protected by patents. Before the implementation of this project, it is advisable to check the operation of such a piston on a model made from a fringed winding according to the technology available today.