Magnet and superconductor development for a high power SMES based power modulator

A superconducting magnetic energy storage (SMES) based power modulator is being developed by the Forschungszentrum Karlsruhe for the proposed TESLA (TeV Superconducting Linear Accelerator) project, under development at the Research Centre DESY, Hamburg. Given the high power (25 MW), high dB/dt (above 50 T/s) pulses required for this application, a cored Rutherford cable with copper oxide insulated strands of mixed matrix NbTi conductor was chosen, to minimize AC losses. The modulator magnet will utilize a structure to provide good cooling of the liquid helium cooled conductor. Optimization of the magnet system with respect to stray magnetic field and costs has led us to choose two solenoids in antiparallel orientation. A test solenoid was constructed and tested, to measure conductor performance and AC losses. The current distribution in the individual strands of the cable was measured at different current ramp rates, through the use of low resistance shunts. Results of these tests and calculations are presented, along with details of the full sized magnets for the modulator.