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  • Open Access

Multi-MA Fusion Accelerator Performance Insensitivity to Electrode Contamination

Nathan P. Brown*, David C. Fairchild, Christopher A. Jennings, Leah N. Appelhans, Jacob T. Banasek, and Nichelle Bennett

  • Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185-1189, USA

  • *Contact author: npbrown@sandia.gov
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PRX Energy 5, 043006 – Published 10 November, 2026

DOI: https://doi.org/10.1103/hkpv-c3y7

Abstract

We provide experimental support for a recent kinetic model study [N. Bennett and D. Welch, Phys. Plasma 32 (2025)] that unexpectedly reported the insensitivity of a multi-MA pulsed power magneto-inertial confinement fusion target to the final power feed contaminant inventory. We measured a 1% difference between the peak current coupled to the target by a nominal high-inductance inner magnetically insulated transmission line (MITL) and the peak current coupled to the target by a contaminated inner MITL in 18 MA experiments on the Z Pulsed Power Facility. We contaminated the inner MITL by adding a net 25 layers of atoms to the anode and cathode current-carrying surfaces via self-assembled monolayer formation of octylphosphonic acid (PO3C8H19) and verified the contaminant’s presence and behavior via x-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and in situ streaked visible spectroscopy. Our findings reinforce the emerging MITL physics description gleaned from recent kinetic simulations, and our efforts provide a method for testing wall contaminant sensitivity that may be adapted for other plasma-facing applications.

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Popular Summary

Pulsed-power accelerators employ large electrical currents to drive fusion reactions. The fusion performance is strongly dependent on the peak current coupled to the target, but the peak current is limited by current-shunting plasmas that are seeded by electrode contaminants. In this work, the authors provide experimental support for an unexpected prediction made by a computational model: that the current lost to these plasmas can be insensitive to increases in the near-target electrode contamination. They tested this prediction by measuring the current delivered to a fusion target on the Z Pulsed Power Facility after adding electrode contamination in a controlled manner.

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PRX Energy 5, 043006– Published 10 November, 2026
  • Received 23 July 2026
  • Revised 25 September 2026
  • Accepted 8 October 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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