Design and performance of the FEMP-2000: a fast risetime, 2 MV EMP pulser

Abstract

The FEMP-2000 pulser is a fast risetime EMP generator designed to drive a horizontally polarized dipole antenna. The pulser is operated at the center of the dipole antenna, typically 30 meters above the ground. It is lightweight and specifically engineered to be easily transportable. The Marx generator and pulse compression stages are located in one end of a biconic structure that is symmetric in area and mass. This EMP generator delivers a double exponential waveform with a peak voltage adjustable between 0.5 and 2 MV into a matched 150 ohm load. It has a risetime below 1 ns (10-90%) and an e-fold decay time of 75 ns. The fast risetime output is achieved through three stages of pulse compression. The system is powered from the ground by a hydraulic motor and an onboard generator subsystem. It is fully remotely controlled through pneumatics and fiber optics, so the operator can turn the system on and off and make all adjustments required from ground level to change the output voltage. The generator is very reproducible in risetime and peak amplitude (within 5%) over the entire 4:1 operating voltage range, while the shot-to-shot RMS throughput delay jitter of the system is less than 9 nS over this range as well. Pulser performance and design details are presented.