Design of non-destructive pulsed magnets at the Dresden High Magnetic Field Laboratory

The Dresden High Magnetic Field Laboratory (HLD) is a user facility which provides external users with the possibility of performing diverse experiments in pulsed magnetic field. Various experimental techniques, such as electrical transport, magnetization, ultrasound and magnetic-resonance measurements are available or are under installation at the HLD. A particular feature of the laboratory is a nearby free-electron laser facility which enables high-field infrared spectroscopy in pulsed magnetic fields [1].
A 50 MJ modular capacitor bank with a maximum charging voltage of 24 kV is in operation at the HLD. This capacitor bank allows to energize independently up to four sub-coils in multi-coil configurations and the energy pulses can be switched to five experimental cells. A program of the non-destructive pulsed magnets for the HLD includes a wide spectrum of coils designed for energies between 1 and 46 MJ, magnetic fields of 60 – 100 T, pulse durations of 10 - 1000 ms, and magnet bores in the range from 20 to 40 mm. In order to fulfill this program the necessary infrastructure accounting for the technical and technological aspects of pulsed-magnet design and fabrication has been established at the HLD. A pulsed-magnet core design has been developed [2]. In spite of the strong external mechanical support, our magnets are designed in a compact way which is suitable both for a mono-coil and a multi-coil configuration. With this design we are trying to achieve higher fields with longer pulse duration and high field homogeneity as well as to provide adequate space inside the magnet for the experimental installations. Important issues of the pulsed-magnet design are numerical simulations of the magnet performance. Both analytical approaches and finite-element analysis are used for these simulations.
Currently a number of 60 T /1.44 MJ and 70 T /8.5 MJ pulsed-magnets are available for external users and for in-house research [3]. A fabrication of a 60 T /43 MJ “long pulse” mono-coil is near to completion. A few double-coil prototypes have been designed, constructed and tested in frame of our 100 T project. Using the test results some improvements have been implemented in the multi-coil configuration. New double-coil prototypes targeting magnetic field above 90 T are under construction now.