Roads to 100 T pulsed magnets
The primary reasons for failure of pulsed magnets are excess heating and stresses due to the Lorentz forces. Thus, uniform heating and constant stress through all layers will improve the performance of a magnet. Here, a computer code is introduced to optimize the magnetic field of a pulsed magnet based on the type and dimensions of the conductor layers, and thickness of the reinforcement layers. Dimensions of each conductor layer are computed to achieve uniform final maximum temperature for all layers. Internal reinforcement thickness along with the type of each conductor are calculated based on the maximum stress in the reinforcement and the maximum elongation in the conductor. The program uses the finite difference Newton's method to find the optimum solution. This program was applied for the design of a 10 layer pulsed magnet with an 11 mm bore diameter. Copper-stainless steel wires were used for the conductors (with different percentage of steel resulting from the optimization) and a multiphase high strength alloy was utilized for the internal layer reinforcement. The results show that a 100 T field can be attained (with a bank energy of 1.9 MJ) by permitting a maximum final temperature of 400 K and maximum von Mises stress of 2.60 GPa.