Pulse Magnet Development Program at NHMFL

Abstract

In 1989, the NHMFL pulsed magnetic field user facility was set up at the Los Alamos National Laboratory. Two programs were initially conceived: 1) The construction of a 60 T long pulse magnet energized by the 600 MJ, 540 MW generator, and 2) a high field magnet program for the 1.6 MJ/32 mF capacitor bank with an operating range of 10 kV. These magnets are designed and built at the NHMFL. Our pulse coil development has its roots in the work accomplished by the group in Leuven which served as a starting point for our technical development programs. After having established the technology, we have focused our efforts on increased reliability. Our present user magnet design is based upon the use of distributed MP35N and Zylon reinforcement. These 60 T short pulse (5.7 ms pulse rise time) and 50 T mid-pulse (40 ms pulse rise time) magnets have become the "workhorse" magnets of the pulsed magnetic field user facility since the failure of the first 60 T long pulse magnet. Coil longevities of 1500 shots, of which half are at full field, are becoming the standard. Presently, the short pulse group is engaged in several programs to increase the science opportunities at our user facility. The development activities encompass fast-cool magnet systems, allowing a shot at least every 20 minutes, the production of a new generation of user coils for higher fields, and a 100 T insert. We present a technical overview of our development programs and new coil designs, including materials development and characterization, identifying those areas critical to progress toward even more reliable and stronger magnetic fields.