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Title: Measuring Plasma Formation Field Strength and Current Loss in Pulsed Power Diodes

Abstract

This LDRD investigated plasma formation, field strength, and current loss in pulsed power diodes. In particular the Self-Magnetic Pinch (SMP) e-beam diode was studied on the RITS-6 accelerator. Magnetic fields of a few Tesla and electric fields of several MV/cm were measured using visible spectroscopy techniques. The magnetic field measurements were then used to determine the current distribution in the diode. This distribution showed that significant beam current extends radially beyond the few millimeter x-ray focal spot diameter. Additionally, shielding of the magnetic field due to dense electrode surface plasmas was observed, quantified, and found to be consistent with the calculated Spitzer resistivity. In addition to the work on RITS, measurements were also made on the Z-machine looking to quantify plasmas within the power flow regions. Measurements were taken in the post-hole convolute and final feed gap regions on Z. Dopants were applied to power flow surfaces and measured spectroscopically. These measurements gave species and density/temperature estimates. Preliminary B-field measurements in the load region were attempted as well. Finally, simulation work using the EMPHASIS, electromagnetic particle in cell code, was conducted using the Z MITL conditions. The purpose of these simulations was to investigate several surface plasma generations models undermore » Z conditions for comparison with experimental data.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [2]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.
  2. Weizmann Inst. of Science, Rehovot (Israel)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1409920
Report Number(s):
SAND-2017-12565
658859
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Johnston, Mark D., Patel, Sonal G., Falcon, Ross Edward, Cartwright, Keith, Kiefer, Mark L., Cuneo, Michael E., and Maron, Yitzhak. Measuring Plasma Formation Field Strength and Current Loss in Pulsed Power Diodes. United States: N. p., 2017. Web. doi:10.2172/1409920.
Johnston, Mark D., Patel, Sonal G., Falcon, Ross Edward, Cartwright, Keith, Kiefer, Mark L., Cuneo, Michael E., & Maron, Yitzhak. Measuring Plasma Formation Field Strength and Current Loss in Pulsed Power Diodes. United States. doi:10.2172/1409920.
Johnston, Mark D., Patel, Sonal G., Falcon, Ross Edward, Cartwright, Keith, Kiefer, Mark L., Cuneo, Michael E., and Maron, Yitzhak. Wed . "Measuring Plasma Formation Field Strength and Current Loss in Pulsed Power Diodes". United States. doi:10.2172/1409920. https://www.osti.gov/servlets/purl/1409920.
@article{osti_1409920,
title = {Measuring Plasma Formation Field Strength and Current Loss in Pulsed Power Diodes},
author = {Johnston, Mark D. and Patel, Sonal G. and Falcon, Ross Edward and Cartwright, Keith and Kiefer, Mark L. and Cuneo, Michael E. and Maron, Yitzhak},
abstractNote = {This LDRD investigated plasma formation, field strength, and current loss in pulsed power diodes. In particular the Self-Magnetic Pinch (SMP) e-beam diode was studied on the RITS-6 accelerator. Magnetic fields of a few Tesla and electric fields of several MV/cm were measured using visible spectroscopy techniques. The magnetic field measurements were then used to determine the current distribution in the diode. This distribution showed that significant beam current extends radially beyond the few millimeter x-ray focal spot diameter. Additionally, shielding of the magnetic field due to dense electrode surface plasmas was observed, quantified, and found to be consistent with the calculated Spitzer resistivity. In addition to the work on RITS, measurements were also made on the Z-machine looking to quantify plasmas within the power flow regions. Measurements were taken in the post-hole convolute and final feed gap regions on Z. Dopants were applied to power flow surfaces and measured spectroscopically. These measurements gave species and density/temperature estimates. Preliminary B-field measurements in the load region were attempted as well. Finally, simulation work using the EMPHASIS, electromagnetic particle in cell code, was conducted using the Z MITL conditions. The purpose of these simulations was to investigate several surface plasma generations models under Z conditions for comparison with experimental data.},
doi = {10.2172/1409920},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Nov 01 00:00:00 EDT 2017},
month = {Wed Nov 01 00:00:00 EDT 2017}
}

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