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Title: Effects of a Conducting Wall on Z-Pinch Stability

Here, the stabilizing effect of a conducting wall on Z-pinch stability has been investigated through a systematic experimental and numerical study. Numerical simulations of a Z-pinch with a cylindrical conducting wall are compared with a case that modeled perforations in the conducting wall. The conducting wall also acts as the return current path for these investigations. Plasma conditions with various pinch sizes were studied numerically to better understand the effect of wall stabilization in Z-pinches. A study using the ZaP Flow Z-Pinch was performed by inserting a 0.35-m perforated section of electrode that has eight longitudinal slots cut from the outer electrode, reducing the conducting wall material by ≈70% .This modification prevents currents from flowing freely along the azimuthal distance of the outer electrode required to stabilize the m = 1, 2, 3 modes, which are experimentally monitored. Operating with identical experimental parameters with and without the perforated electrode was assumed to produce similar equilibrium and flow shear conditions in the pinch. Comparing the stability characteristics isolated the potential effects of the conducting wall. Magnetic data, interferometry, and optical images indicate that the conducting wall does not have a discernible effect on stability in the ZaP experiment. This result agreesmore » with simulations with similar ratios of conducting wall radius to pinch radius.« less
Authors:
 [1] ;  [2] ; ORCiD logo [3]
  1. Univ. of Washington, Seattle, WA (United States); Pennsylvania State Univ., University Park, PA (United States). Applied Research Lab.
  2. Univ. of Washington, Seattle, WA (United States); Applied Research Associates, Inc., Albuquerque, NM (United States)
  3. Univ. of Washington, Seattle, WA (United States). Aerospace and Energetics Research Program
Publication Date:
Grant/Contract Number:
NA0001860
Type:
Accepted Manuscript
Journal Name:
IEEE Transactions on Plasma Science
Additional Journal Information:
Journal Volume: 42; Journal Issue: 6; Journal ID: ISSN 0093-3813
Publisher:
IEEE
Research Org:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA); US Air Force Office of Scientific Research (AFOSR)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 42 ENGINEERING; magnetohydrodynamics (MHD); wall stabilization; Z-pinch; electrodes; stability analysis; numerical stability; plasmas; magnetic resonance imaging; geometry; optical interferometry
OSTI Identifier:
1465212

Knecht, Sean D., Lowrie, Weston, and Shumlak, Uri. Effects of a Conducting Wall on Z-Pinch Stability. United States: N. p., Web. doi:10.1109/TPS.2014.2320923.
Knecht, Sean D., Lowrie, Weston, & Shumlak, Uri. Effects of a Conducting Wall on Z-Pinch Stability. United States. doi:10.1109/TPS.2014.2320923.
Knecht, Sean D., Lowrie, Weston, and Shumlak, Uri. 2014. "Effects of a Conducting Wall on Z-Pinch Stability". United States. doi:10.1109/TPS.2014.2320923. https://www.osti.gov/servlets/purl/1465212.
@article{osti_1465212,
title = {Effects of a Conducting Wall on Z-Pinch Stability},
author = {Knecht, Sean D. and Lowrie, Weston and Shumlak, Uri},
abstractNote = {Here, the stabilizing effect of a conducting wall on Z-pinch stability has been investigated through a systematic experimental and numerical study. Numerical simulations of a Z-pinch with a cylindrical conducting wall are compared with a case that modeled perforations in the conducting wall. The conducting wall also acts as the return current path for these investigations. Plasma conditions with various pinch sizes were studied numerically to better understand the effect of wall stabilization in Z-pinches. A study using the ZaP Flow Z-Pinch was performed by inserting a 0.35-m perforated section of electrode that has eight longitudinal slots cut from the outer electrode, reducing the conducting wall material by ≈70% .This modification prevents currents from flowing freely along the azimuthal distance of the outer electrode required to stabilize the m = 1, 2, 3 modes, which are experimentally monitored. Operating with identical experimental parameters with and without the perforated electrode was assumed to produce similar equilibrium and flow shear conditions in the pinch. Comparing the stability characteristics isolated the potential effects of the conducting wall. Magnetic data, interferometry, and optical images indicate that the conducting wall does not have a discernible effect on stability in the ZaP experiment. This result agrees with simulations with similar ratios of conducting wall radius to pinch radius.},
doi = {10.1109/TPS.2014.2320923},
journal = {IEEE Transactions on Plasma Science},
number = 6,
volume = 42,
place = {United States},
year = {2014},
month = {5}
}