Resistive Solenoid Development at the NHMFL Based on Irregular Stacking Method

The National High Magnetic Field Laboratory (NHMFL) in Tallahassee, Florida designs, builds and operates the world's highest field dc resistive magnets, providing fields up to 36 T in pure resistive systems and up to 45 T in resistive-superconducting hybrids. The NHMFL has several resistive solenoid magnet projects underway presently, including upgrading existing magnets, designing the conical insert for the Helmholtz Center Berlin (HZB), and designing insert coils of the Series-Connected-Hybrid (SCH) for NHMFL. In addition, building the 28 MW all resistive magnets will start in 2012. The method, called irregular stacking, successfully used in the upgrade of the existing magnets in 2009, will be employed in the new upgrades and the design of the new magnet system. In this paper, the progresses of each project are briefly summarized at first. The new technology of irregular stacking is then discussed in detail. In the last section, the application of the technology in future upgrades and the design of the magnets are present.