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Title: Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap

Abstract

We present an experimental analysis of the symmetry of current density in a coaxial geometry, diagnosed using a magnetic field probe array and calculations of the Fowler-Nordheim enhancement factor. Data were collected on the coaxial gap breakdown device (240 A, 25 kV, 150 ns, ~0.1 Hz), and data from experiments using 2 different gap sizes and different penetration depths are compared over runs comprising 50 shots for each case. The magnetic field probe array quantifies the distribution of current density at three axial locations, on either sides of a vacuum breakdown, and tracks the evolution with time and space. The results show asymmetries in current density, which can be influenced by changes in the gap size and the penetration depth (of the center electrode into the outer electrode). For smaller gap sizes (400 μm), symmetric current profiles were not observed, and the change in the penetration depth changes both the symmetric behavior of the current density and the enhancement factor. For larger gaps (900 μm), current densities were typically more uniform and less influenced by the penetration depth, which is reflected in the enhancement factor values. Furthermore it is possible that the change in inductance caused by the localization ofmore » current densities plays a role in the observed behavior.« less

Authors:
 [1];  [1]
  1. Univ. of California San Diego, La Jolla, CA (United States)
Publication Date:
Research Org.:
Cornell Univ., Ithaca, NY (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1511020
Alternate Identifier(s):
OSTI ID: 1411983
Grant/Contract Number:  
FC03-02NA00057
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 122; Journal Issue: 21; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Citation Formats

Cordaro, S. W., and Bott-Suzuki, S. C. Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap. United States: N. p., 2017. Web. doi:10.1063/1.5002698.
Cordaro, S. W., & Bott-Suzuki, S. C. Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap. United States. doi:10.1063/1.5002698.
Cordaro, S. W., and Bott-Suzuki, S. C. Thu . "Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap". United States. doi:10.1063/1.5002698. https://www.osti.gov/servlets/purl/1511020.
@article{osti_1511020,
title = {Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap},
author = {Cordaro, S. W. and Bott-Suzuki, S. C.},
abstractNote = {We present an experimental analysis of the symmetry of current density in a coaxial geometry, diagnosed using a magnetic field probe array and calculations of the Fowler-Nordheim enhancement factor. Data were collected on the coaxial gap breakdown device (240 A, 25 kV, 150 ns, ~0.1 Hz), and data from experiments using 2 different gap sizes and different penetration depths are compared over runs comprising 50 shots for each case. The magnetic field probe array quantifies the distribution of current density at three axial locations, on either sides of a vacuum breakdown, and tracks the evolution with time and space. The results show asymmetries in current density, which can be influenced by changes in the gap size and the penetration depth (of the center electrode into the outer electrode). For smaller gap sizes (400 μm), symmetric current profiles were not observed, and the change in the penetration depth changes both the symmetric behavior of the current density and the enhancement factor. For larger gaps (900 μm), current densities were typically more uniform and less influenced by the penetration depth, which is reflected in the enhancement factor values. Furthermore it is possible that the change in inductance caused by the localization of current densities plays a role in the observed behavior.},
doi = {10.1063/1.5002698},
journal = {Journal of Applied Physics},
number = 21,
volume = 122,
place = {United States},
year = {2017},
month = {12}
}

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