Megagauss magnetic field generation in single-turn coils:: new frontiers for scientific experiments

We report on the design and performance of a megagauss generator at the Humboldt High Magnetic Field Centre. The installation uses the fast capacitor discharge into single-turn coils to produce microsecond pulses of 260 T in 8 mm diameter suitable for low-temperature experiments and 310 T in 5 mm diameter. Simple concepts are applied to substantiate crucial design principles for the generator and the choice of components. The implementation of a high-power/low-inductance circuit operated at 60 kV and other technical questions are discussed in detail. The analysis of experimental field and current data is based on numerical simulations of the magnetic pressure and the nonlinear flux diffusion. It was carried out in order to investigate the limitations and characteristics of the Berlin generator in particular and the single-turn coil technique in general. The paper focuses primarily on field, generator and coil parameters, which can be used for performing routine, reproducible scientific experiments at low temperatures.