Series fault limiting resistors for Atlas Marx modules

The proposed Atlas pulsed power supply design provides a current pulse to the experiment chamber from a set of 20, 3-Marx-unit-wide modules radially positioned around a rectangular disk transmission-line system (total of 60 Marxes in parallel). The Atlas circuit is designed to be a near-critically-damped network with a total erected capacitance of 200 /spl mu/F at 600 kV. The justification for the necessary circuit resistance in this approach is based on reliability, fault tolerance and operational maintenance. Also the use of high energy-density capacitors that have lower tolerance to voltage reversal is a primary reason for the damping provided by significant series resistance. To obtain the damping there are two system resistors in the Atlas design. One resistor is a shunt element designed to damp the resonance caused by the relatively high-Q disk transmission-line capacitance and the Marx bank inductance. The second, more significant resistor is a series, fault-current limiting element that also performs the necessary damping for voltage reversal at the bank capacitors. The series resistor is the subject of this paper.