A laboratory instrument for generating magnetic fields over 200 T with single turn coils

Abstract

An instrument has been developed that reliably generates pulsed magnetic fields in the range 150-250 T for experimental applications. A 100 kJ, 40 kV capacitor bank with 18 nH internal inductance and 2.9 m Omega internal resistance is discharged into single turn coils made of copper sheet of 3 mm thickness. 150 T are obtained in 10 mm diameter with a rise time (quarter period) of 2.5 mu s, 200 T are obtained in 6 mm ID within 2 mu s and 250 T in 4 mm ID within 1.8 mu s. Although the coils explode violently and generate a strong axial blast, there is no movement towards the magnetic field volume and even delicate samples can easily be protected to survive an experiment unharmed. This is demonstrated with two experiments: infra-red cyclotron resonance in a GaAs-AlGaAs superlattice and Faraday rotation in GaP.