Conference Agenda

The Orion Laser Facility has been operational for 16 years, amassing a large cache of pulsed power shot data which stands to yield useful information relating to the failures and trends within the Capacitor Bank Modules (CBMs).

The data is the derived from the integration of Rogowski coils measurements of the current on each pulse forming line to the loads as well as the spark gaps used for triggering the discharge of the CBM. These are used to detect failures on the load with variations with current amplitude, time base and ringing post-shot.

With a full dataset, potential symptoms may be observed before failures as well as trends that have occurred over the operational life of Orion. This can help to understand the aging of the system and avoid the normalisation of failures that may be unknown to system users.

This work shall cover the processing and interpretation of the data produced, outline the general trends both through life and leading up to failures, and the advantages of analysing the system across the whole dataset, instead of individual datasets.

UK Ministry of Defence © Crown owned copyright 2026/AWE

Pulsed power systems require electrical contacts that can withstand high voltage stresses, high currents, and rapid current transients. In coaxial and lamella-based connectors, nanosecond transients amplify current crowding associated with skin effect, potentially compromising contact reliability and efficiency.
This work investigates the interplay between contact geometry and material properties to mitigate localized heating and voltage drops. Finite-element simulations, RF characterization, and pulsed measurements are conducted to evaluate how specific surface coatings and interface geometries influence time-dependent impedance and loss mechanisms.
The study identifies critical performance parameters and provides a set of design guidelines for high-current, fast-pulse applications.

The space-charge-limited current (SCLC), which corresponds to the maximum steady-state current permissible in a diode, is well understood in vacuum and semiconductors [P. Zhang et al., J. Appl. Phys. 129, 100902 (2021)]. Recent studies have derived an exact theory to predict the SCLC for a general collision frequency that can range from vacuum to solid [L. I. Breen and A. L. Garner, Phys. Plasmas 31, 032102 (2024)]. However, all these derivations assume that there is a single material between the cathode and anode with a specific collision frequency. Chandra and Ang [Appl. Phys. Lett. 96, 183501 (2010)] derived a solution for two media placed between the electrodes, but they only considered the combination of a solid (purely driven by Mott-Gurney) and perfect vacuum. This approach does not address a situation where one of the electrodes may erode, resulting in the formation of a plasma with some nonzero, but not large (e.g., a solid) collision frequency due to plasma formation. In this presentation, we extend the derivation for the SCLC with general collision frequency to consider two different materials with . We recover the vacuum limit when we set both materials to and the semiconductor limit when we set both regimes to . We demonstrate that the more collisional material drives the SCLC even when it composes a small portion of the total gap distance. Implications on device design and failure will be discussed.

This work was supported by JDETO under Contract HQ0642384797, SCALE: U.S. DoD under Contract W52P1J-22-9-3009, and Sandia National Laboratories, which is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.