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Results for “EXPLODING WIRES”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Simulating the effects of underground nuclear explosions with an exploding wire

Exploding wires can deposit significant amounts of energy (1000’s of Joules on a nano-microsecond timescales) into a very confined space. Under the right conditions they can even produce neutrons. While most exploding wire studies have been performed in open air and to a lesser extent liquids we have started to investigate enclosing the wire element in solid matrices like concrete to mimic the effects of an underground nuclear explosion. The temperatures and pressures achieved are quite sufficient to induce structural cracking and localized flash melting in the enclosing media like a real underground nuclear detonation. As a result exploding wires would appear to form the perfect trigger for releasing confined chemical species including gases in geological media to study migration behavior in a controlled environment. Details of the apparatus and some illustrations of it potential will be given.

Underground Nuclear Explosions, Exploding Wires, X↗
DOE OSTI2017

Power and energy of exploding wires

Exploding wires are used in many high-energy applications, such as initiating explosives. Previous work analyzing gold wire burst in detonator applications has shown burst current and action metrics to be inconsistent with burst phenomenon across multiple firing-sets. Energy density better captures the correlation between different wire geometries, different electrical inputs, and explosive initiation. This idea has been expanded upon, to analyze the burst properties in power-energy space. Further inconsistencies in the understanding of wire burst and its relation to peak voltage have been found. An argument will be made for redefining the definition of burst. The result is a more broad understanding of rapid metal phase transition and the initiation of explosives in EBW applications.

42 ENGINEERING↗
DOE OSTI2011

High resolution absorption spectroscopy of exploding wire plasmas using an x-pinch x-ray source and spherically bent crystal

We present here the use of absorption spectroscopy of the continuum radiation from x-pinch-produced point x-ray sources as a diagnostic to investigate the properties of aluminum plasmas created by pulsed power machines. This technique is being developed to determine the charge state, temperature, and density as a function of time and space under conditions that are inaccessible to x-ray emission spectroscopic diagnostics. The apparatus and its characterization are described, and the spectrometer dispersion, magnification, and resolution are calculated and compared with experimental results. Spectral resolution of about 5000 and spatial resolution of about 20 {mu}m are demonstrated. This spectral resolution is the highest available to date in an absorption experiment. The beneficial properties of the x-pinch x-ray source as the backlighter for this diagnostic are the small source size (<5 {mu}m), smooth continuum radiation, and short pulse duration (<0.1 ns). Results from a closely spaced (1 mm) exploding wire pair are shown and the general features are discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Validation of Exploding Wire Tests Using Alegra-NG

Exploding wire tests are used to characterize materials undergoing high voltage loading and to validate computational models in a simple configuration. In this report, the materials emphasized are gold, aluminum, copper and nickel wires. Model validation is presented using the nominal model (no uncertainty) in the form of heat maps (per material) that show model bias across scalar quantities and initial voltage. Mesh convergence and uncertainty quantification is also presented.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Synchrotron radiography of Richtmyer–Meshkov instability driven by exploding wire arrays

We present a new technique for the investigation of shock-driven hydrodynamic phenomena in gases, liquids, and solids in arbitrary geometries. The technique consists of a pulsed power-driven resistive wire array explosion in combination with multi-MHz synchrotron radiography. Compared to commonly used techniques, it offers multiple advantages: (1) the shockwave geometry can be shaped to the requirements of the experiment, (2) the pressure (P > 300 MPa) generated by the exploding wires enables the use of liquid and solid hydrodynamic targets with well-characterized initial conditions (ICs), (3) the multi-MHz radiography enables data acquisition to occur within a single experiment, eliminating uncertainties regarding repeatability of the ICs and subsequent dynamics, and (4) the radiographic measurements enable estimation of compression ratios from the x-ray attenuation. In addition, the use of a synchrotron x-ray source allows the hydrodynamic samples to be volumetrically characterized at a high spatial resolution with synchrotron-based microtomography. This experimental technique is demonstrated by performing a planar Richtmyer–Meshkov instability (RMI) experiment on an aerogel–water interface characterized by Atwood number A0∼−0.8 and Mach number M∼1.5. The qualitative and quantitative features of the experiment are discussed, including the energy deposition into the exploding wires, shockwave generation, compression of the interface, startup phase of the instability, and asymptotic growth consistent with Richtmyer's impulsive theory. Additional effects unique to liquids and solids—such as cavitation bubbles caused by rarefaction flows or initial jetting due to small perturbations—are observed. It is also demonstrated that the technique is not shape dependent by driving a cylindrically convergent RMI experiment.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Reconstruction and analysis of exploding wire particle trajectories via automatic calibration of stereo images

Quantitative understanding of the physics of dust or granular matter transport significantly impacts several aspects of burning plasma science and technology. Here, this work takes machine vision techniques popular in robotics and self-driving cars and applies them to identification and analysis of microparticles generated from exploding wires. Using only the image frames and knowledge of the intrinsic properties of the cameras, a Python code was written to identify the particles, automatically calibrate the relative image positions, and extract trajectory data. After identifying approximately 50 particles based on the timing of secondary particle explosions, the eight point and random sample consensus algorithms were used to determine the geometric correlation between the cameras. Over 100 particle matches were found between the two camera views. These correlated trajectories were used in subsequent 3D track reconstruction and analysis of the physics behind the particle motion. The 3D reconstruction resulted in accurate positioning of the particles with respect to the experimental setup. The particle motion was consistent with the effects of a 1 g gravitational field modified by drag forces. Lastly, the methods and analyses presented here can be used in many facets of high temperature plasma diagnostics.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2019

Core structure and secondary breakdown of an exploding wire in the current-pause regime

The results of experiments with rapidly exploding thin conductors inthe current-pause regime are presented. Copper wires 25μm in diameter and 12 mm in length serve as loads for a GVP pulsed generator based on a low-inductance capacitor. The generator produces current pulses of up to 10 kA with dI/dt up to 50 A/ns. A 100–800-ns current-pause regime is obtained for charging voltages of 10–15 kV. The discharge channel structure is studied by shadow photography using 0.53-μm, 10-ns second-harmonic pulses from a Nd 3+ :YAG laser. In the experiments, three types of secondary breakdown are observed, with different symmetry types, different current-pause durations, and different dependences on the energy deposited into the wire during its resistive heating. All of these breakdown types develop inside a tubular core that is produced in the current-pause stage and that remains almost undamaged by the breakdown.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Assessment of Proton Deflectometry for Exploding Wire Experiments

This project provides the first demonstration of the application of proton deflectometry for the diagnosis of electromagnetic field topology and current-carrying regions in Z-pinch plasma experiments. Over the course of this project several milestones were achieved. High-energy proton beam generation was demonstrated on the short-pulse high-intensity Leopard laser, (10 Joules in ~350 femtoseconds, and the proton beam generation was shown to be reproducible. Next, protons were used to probe the electromagnetic field structure of short circuit loads in order to benchmark the two numerical codes, the resistive-magnetohydrodynamics (MHD) code, Gorgon, and the hybrid particle-in-cell code, LSP for the interpretation of results. Lastly, the proton deflectometry technique was used to map the magnetic field structure of pulsed-power-driven plasma loads including wires and supersonic jets formed with metallic foils. Good agreement between the modeling and experiments has been obtained. The demonstrated technique holds great promise to significantly improve the understanding of current flow and electromagnetic field topology in pulsed power driven high energy density plasmas. Proton probing with a high intensity laser was for the first time implemented in the presence of the harsh debris and x-ray producing z-pinch environment driven by a mega-ampere-scale pulsed-power machine. The intellectual merit of the program was that it investigated strongly driven MHD systems and the influence of magnetic field topology on plasma evolution in pulsed power driven plasmas. The experimental program involved intense field-matter interaction in the generation of the proton probe, as well as the generation of plasma subjected to 1 MegaGauss scale magnetic fields. The computational aspect included two well-documented codes, in combination for the first time to provide accurate interpretation of the experimental results. The broader impact included the support of 2 graduate students, one at UCSD and one at NTF, who were exposed to both the experimental physics work, the MHD and PIC modeling of the system. A first generation college undergraduate student was employed to assist in experiments and data analysis throughout the project. Data resulting from the research program were broadly disseminated by publication in scientific journals, and presentation at international and national conferences and workshops.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Improved Solver Settings for 3D Exploding Wire Simulations in ALEGRA

We are interested in simulating a variety of problems in 3 dimensions (3D) featuring large electric currents. While 2D simulations have been quite informative, cylindrical symmetry may interfere with a problem’s relevant physics. Specifically, all objects in the domain behave as if they are extruded 360°—turning particles into hoops. In dealing with electrical current, this can have serious ramifications on the current pathways. In 3D (r, φ, z) currents can adjust their pathways anywhere along those 360 degrees given the right conditions; however, in 2D (r, z) those pathways can be completely choked off because an insulating hoop, rather than a particle, is present.

42 ENGINEERING↗
DOE OSTI2026

Pairing Simulation with Uncertainty Quantification for Exploding Wire Tests

In a 2025 SAND report by Carnes et al., it was observed that experimental and model results were not in agreement, especially peak voltage, and time of peak, for gold, with observed disagreements of up to 40%. In this work, we investigate whether other sources of uncertainty in the model can explain this disagreement between experiment and model.

Mendoza, Hector Javier [Sandia National Laboratori↗