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Title: The impact of plasma dynamics on the self-magnetic-pinch diode impedance

Abstract

The self-magnetic-pinch diode is being developed as an intense electron beam source for pulsed-power-driven x-ray radiography. The basic operation of this diode has long been understood in the context of pinched diodes, including the dynamic effect that the diode impedance decreases during the pulse due to electrode plasma formation and expansion. Experiments being conducted at Sandia National Laboratories' RITS-6 accelerator are helping to characterize these plasmas using time-resolved and time-integrated camera systems in the x-ray and visible. These diagnostics are analyzed in conjunction with particle-in-cell simulations of anode plasma formation and evolution. The results confirm the long-standing theory of critical-current operation with the addition of a time-dependent anode-cathode gap length. The results may suggest that anomalous impedance collapse is driven by increased plasma radial drift, leading to larger-than-average ion v{sub r} × B{sub θ} acceleration into the gap.

Authors:
; ; ; ; ; ; ;  [1];  [2]; ; ; ; ; ; ; ; ;  [3]
  1. National Security Technologies, LLC, Las Vegas, Nevada 89193 (United States)
  2. Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States)
  3. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
Publication Date:
OSTI Identifier:
22408242
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATORS; ANODES; CAMERAS; CATHODES; COMPUTERIZED SIMULATION; CRITICAL CURRENT; ELECTRON BEAMS; PINCH DEVICES; PLASMA; PLASMA EXPANSION; PULSES; SANDIA NATIONAL LABORATORIES; TIME DEPENDENCE; TIME RESOLUTION; X-RAY RADIOGRAPHY

Citation Formats

Bennett, Nichelle, Crain, M. Dale, Droemer, Darryl W., Gignac, Raymond E., Molina, Isidro, Obregon, Robert, Smith, Chase C., Wilkins, Frank L., Welch, Dale R., Webb, Timothy J., Mazarakis, Michael G., Kiefer, Mark L., Johnston, Mark D., Leckbee, Joshua J., Nielsen, Dan, Romero, Tobias, Simpson, Sean, and Ziska, Derek. The impact of plasma dynamics on the self-magnetic-pinch diode impedance. United States: N. p., 2015. Web. doi:10.1063/1.4916062.
Bennett, Nichelle, Crain, M. Dale, Droemer, Darryl W., Gignac, Raymond E., Molina, Isidro, Obregon, Robert, Smith, Chase C., Wilkins, Frank L., Welch, Dale R., Webb, Timothy J., Mazarakis, Michael G., Kiefer, Mark L., Johnston, Mark D., Leckbee, Joshua J., Nielsen, Dan, Romero, Tobias, Simpson, Sean, & Ziska, Derek. The impact of plasma dynamics on the self-magnetic-pinch diode impedance. United States. doi:10.1063/1.4916062.
Bennett, Nichelle, Crain, M. Dale, Droemer, Darryl W., Gignac, Raymond E., Molina, Isidro, Obregon, Robert, Smith, Chase C., Wilkins, Frank L., Welch, Dale R., Webb, Timothy J., Mazarakis, Michael G., Kiefer, Mark L., Johnston, Mark D., Leckbee, Joshua J., Nielsen, Dan, Romero, Tobias, Simpson, Sean, and Ziska, Derek. Sun . "The impact of plasma dynamics on the self-magnetic-pinch diode impedance". United States. doi:10.1063/1.4916062.
@article{osti_22408242,
title = {The impact of plasma dynamics on the self-magnetic-pinch diode impedance},
author = {Bennett, Nichelle and Crain, M. Dale and Droemer, Darryl W. and Gignac, Raymond E. and Molina, Isidro and Obregon, Robert and Smith, Chase C. and Wilkins, Frank L. and Welch, Dale R. and Webb, Timothy J. and Mazarakis, Michael G. and Kiefer, Mark L. and Johnston, Mark D. and Leckbee, Joshua J. and Nielsen, Dan and Romero, Tobias and Simpson, Sean and Ziska, Derek},
abstractNote = {The self-magnetic-pinch diode is being developed as an intense electron beam source for pulsed-power-driven x-ray radiography. The basic operation of this diode has long been understood in the context of pinched diodes, including the dynamic effect that the diode impedance decreases during the pulse due to electrode plasma formation and expansion. Experiments being conducted at Sandia National Laboratories' RITS-6 accelerator are helping to characterize these plasmas using time-resolved and time-integrated camera systems in the x-ray and visible. These diagnostics are analyzed in conjunction with particle-in-cell simulations of anode plasma formation and evolution. The results confirm the long-standing theory of critical-current operation with the addition of a time-dependent anode-cathode gap length. The results may suggest that anomalous impedance collapse is driven by increased plasma radial drift, leading to larger-than-average ion v{sub r} × B{sub θ} acceleration into the gap.},
doi = {10.1063/1.4916062},
journal = {Physics of Plasmas},
number = 3,
volume = 22,
place = {United States},
year = {Sun Mar 15 00:00:00 EDT 2015},
month = {Sun Mar 15 00:00:00 EDT 2015}
}