A Practical Variable-Stage Megajoule-Class Marx Generator Using Commercial Ignitrons

Abstract

Megajoule-class pulsed power systems that require rapid rate-of-rise of multi-kiloamp current demand switches that operate faster than conventional semiconductor switches can achieve. This paper presents a system that uses ignitrons to control high di/dt sub-millisecond pulses. However, the application at hand involves voltage levels exceeding the limits of commercially available ignitrons, necessitating the stacking or Marxing of multiple capacitor-ignitron modules. Even non-Marxed ignitron-switched pulsed power capacitor banks present a number of inherent challenges, including multi-microsecond trigger jitter, sensitivity to physical handling, and temperature-related performance variability. Most Marxed pulsed power banks have a fixed topology and are optimized for one particular load. Because the bank outlined here is used for research and development involving loads with differing characteristics, a further requirement is the ability to configure the bank for use in non-Marxed parallel modules, a Marx bank stacked two modules high, and a Marx bank stacked four modules high for greater flexibility. This paper details the successful implementation of a dynamically Marxed ignitron-switched megajoule-class capacitor bank, along with the auxiliary systems developed to address these challenges and create a practical, versatile pulsed power system.