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Modeled sensitivity of multi-MA accelerator performance to electrode contaminant inventory

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/5.0276238· OSTI ID:2584043

Significant particle-in-cell code development has enabled simulations of power flow in multi-MA accelerators to include the desorption of surface contaminants, their ionization into surface plasmas, and the impact of these plasmas on efficiency. The simulations base desorption on an Arrhenius equation, whose most significant unknown is the surface contaminant inventory. The sensitivity of power-flow simulations to this inventory is studied here using Sandia National Laboratories' Z accelerator with a 7-nH MagLIF load [Phys. Plasmas 17, 056303 (2010)]. Simulations are conducted in 3D cylindrical coordinates for the current-adder, or “convolute,” region of Z and in 2D for the final feed only. Simulated contaminant inventories are varied from 1 to 32 monolayers (MLs) in 2D, and 2 to 4 ML in 3D. The results reveal sensitivities to the local ratio of E/B⁠. The high B-field, low E-field region near the short-circuit load is insensitive to the contaminant inventory, where assumed values of 4–32 ML change the load current by ≤ 2%, and agree with experiment to within 2% at peak current. A 1-ML value is the outlier, increasing the load current by 5%, but still within measurement uncertainty. In contrast, the relatively higher E-field, lower B-field convolute region has slower contaminant desorption and higher-magnitude E-field penetration of the surface plasmas. The current loss in the convolute region does increase with contaminant inventory. The loss assuming 4 ML is 12% larger than for 2 ML, with 4 ML being the better match to experiment.

Research Organization:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
Grant/Contract Number:
NA0003525
OSTI ID:
2584043
Alternate ID(s):
OSTI ID: 2585597
Report Number(s):
SAND--2025-06828J; 1775565
Journal Information:
Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 6 Vol. 32; ISSN 1070-664X; ISSN 1089-7674
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

References (29)

Implicit highly-coupled single-ion Hall-MHD formulation for hybrid particle-in-cell codes journal April 2021
Particle-in-cell simulations of electron flow in the post-hole convolute of the Z accelerator journal October 2001
Pulsed-power-driven cylindrical liner implosions of laser preheated fuel magnetized with an axial field journal May 2010
Measurement of electron energy deposition necessary to form an anode plasma in Ta, Ti, and C for coaxial bremsstrahlung diodes journal July 1989
Particle-in-cell simulations of electron beam control using an inductive current divider journal November 2015
Hybrid-PIC modeling of laser-plasma interactions and hot electron generation in gold hohlraum walls journal June 2017
Design and testing of a magnetically driven implosion peak current diagnostic journal April 2018
Tungsten wire-array Z-pinch experiments at 200 TW and 2 MJ journal May 1998
Review of pulsed power-driven high energy density physics research on Z at Sandia journal July 2020
Particle-in-cell simulations of ion dynamics in a pinched-beam diode journal May 2022
Power flow in magnetically insulated transmission lines with ion backscatter effects journal September 2023
Water desorption from rapidly-heated metal oxide surfaces—first principles, molecular dynamics, and the Temkin isotherm journal October 2018
Examining the molecular origins of anomalously high H2O generation at oxide-passivated metal surfaces for plasma applications journal August 2023
The Effect of Space Charge and Residual Gases on Thermionic Currents in High Vacuum journal December 1913
Simulations of the generation and transport of a 5 MV end-point x-ray beam on a pulsed power generator journal May 2019
Electrode contaminant plasma effects in 1 0 7 -A Z pinch accelerators journal July 2019
Current transport and loss mechanisms in the Z accelerator journal December 2019
Fast hybrid particle-in-cell technique for pulsed-power accelerators journal November 2020
Magnetized particle transport in multi-MA accelerators journal June 2021
Electrode plasma formation and melt in Z -pinch accelerators journal April 2023
Efficient kinetic particle simulations of space charge limited emission in magnetically insulated transmission lines using reduced physics models journal September 2023
Understanding the impact of an applied axial magnetic field on efficient current coupling on the Z machine journal October 2024
Plasma evolution and dynamics in high-power vacuum-transmission-line post-hole convolutes journal June 2008
Tailoring of electron flow current in magnetically insulated transmission lines journal March 2009
Steady-state modeling of current loss in a post-hole convolute driven by high power magnetically insulated transmission lines journal December 2013
Computational analysis of current-loss mechanisms in a post-hole convolute driven by magnetically insulated transmission lines journal March 2015
Results of vacuum cleaning techniques on the performance of LiF field-threshold ion sources on extraction applied-B ion diodes at 1-10 TW journal April 1997
Modeling the pump‐down of a reversibly adsorbed phase. I. Monolayer and submonolayer initial coverage journal March 1995
A Fast Implicit Algorithm for Highly Magnetized Charged Particle Motion~!2009-06-25~!2009-10-26~!2010-04-13~! journal April 2010