Investigation on Nonuniformity of Magnetic Field in Curved Coaxial Magnetically Insulated Transmission Line System

Abstract

The curved coaxial magnetically insulated transmission line (MITL) generates nonuniform magnetic fields, causing substantial current loss and nonuniform current in the system. However, the nonuniform magnetic field can recover uniformity with a certain distance after the curved region. In this article, 3-D particle-in-cell simulations were carried out to investigate the mechanism of the recovery of nonuniform magnetic field in the region after the 90°-curved MITL and the factors influencing the distance needed for the recovery of the uniformity of magnetic field. The results indicate that a high-impedance load causes higher nonuniformity of the magnetic field in the MITL after the curved region than the situation with a low-impedance load. The profile of nonuniformity of the magnetic field in the MITL after the curved region transforms from an exponentially decreasing shape to a “W” shape when the MITL operates from a load-limited case to a self-limited case. The distance for the recovery of the nonuniform magnetic field after the 90°-curved MITL is about 2–3 times the radius of the anode, and has no independence with the radii of curvature and cathode. This work fascinates the improvement of magnetic field uniformity in the curved MITL system.