Design of a MITL for a 1 MA LTD Driving a Wire Array Z-Pinch Load

Summary form only given. A self-magnetically insulated transmission line (MITL) has been designed to transmit a 1 MA 100 kV pulse with a 70 ns rise-time from a Linear Transformer Driver (LTD) to a wire array z-pinch load. The transmission line has three stages: a coaxial line, followed by a radial line, and finally a conical line to the load. The transmission line geometry was chosen to ease construction and to lower cost while maintaining a low inductance. Both collisionlessand collisional MITL models were used to determine the lower limit of the anode-cathode gap for the transmission line. A third case assuming vacuum insulation with a limiting electric field of 200 kV/cm in the transmission line was also investigated. The transmission line inductance in each of these cases was calculated analytically, and a PSpice simulation of the circuit was used to compare the performance of the designs. Assuming the z-pinch load inductance was approximately 3 nil, the collisional and collisionless MITL models each met the goal of a 1 MA pulse with a 70 ns rise-time. The vacuum insulation design did not meet these requirements. The anode-cathode gap in the collisional MITL design was expanded until the transmission line inductance reached 4 nH, such that the current pulse shape still met the preset goals and a factor of safety was added to reduce the possibility of arcing. This MITL design will be constructed and implemented on the LTD z-pinch being constructed in 2007 at the University of Michigan.