Speaker
Description
Quasi-force-free magnets, with their small volume and low inductance characteristics, are considered a promising option for the magnetic system in THz gyrotrons. However, the current quasi-force-free magnets suffer from complex structures that are difficult to fabricate. Moreover, due to the inherent instability of their structure, a dielectric with a sufficiently high Young's modulus needs to be filled in the gap to reduce the stress on the conductor below its ultimate strength, which further increasing the fabrication difficulty. Therefore, we propose a design for a quasi-force-free magnet using copper tubes, high-strength steel tubes, and poly(p-phenylene-2,6-benzoxazole) (PBO) fiber reinforcement layers. This design not only simplifies the magnet fabrication process but also eliminates the need for filling high Young's modulus dielectrics. The magnet structure was studied and optimized to meet the ultimate strength limit of the conductor. Firstly, the pitch of the coil was adjusted to subject the conductor to an outward radial electromagnetic force. Then, by winding a PBO fiber reinforcement layer around the magnet and filling a small amount of epoxy resin in the gap, the unbalanced electromagnetic force was counteracted. This enables the quasi-force-free magnet to be fabricated using a process similar to that of common pulse magnets. Simulation results show that this structure of quasi-force-free magnet can generate a strong magnetic field of 50T.
