250-kG mirror coil development for the linear Scyllac experiment

The linear Scyllac theta-pinch machine required mirror coils on each end of the 5-m-long lead coil, which would give mirror ratios of two to three times the 100-kG main coil magnetic field. A pulsed magnetic field of 250 RG was established as a design goal for the mirror coils. Several different designs were evaluated using the 178- kJ, 80-kV Scyllac prototype capacitor bank. Calculations were made to determine the coil geometry for each 250-kG cotl design. A copper-lined, steel-jacketed coil, and an all steel coil were fabricated and tested (4 to 5 cm bores). The types of materials selected for each coli, strength considerations, and fabricating techniques are discussed. The final design of the mirror coils for the 11.2-cm-bore Scyllac machine was established using an all-steel (Maraging type 250) design. An aluminium coil (2014-T652) was built and tested to failure in order to establish data as to the maximum fields that aluminum coils could be subjected to in a typical pulsed theta-pinch evironment. This program and conclusions are discussed. (auth)