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Title: Helical instability in MagLIF due to axial flux compression by low-density plasma

The MagLIF (Magnetized Liner Inertial Fusion) experiment at Sandia National Labs is one of the three main approaches to inertial confinement fusion. Radiographic measurements of the imploding liner have shown helical structuring that was not included in MagLIF scaling calculations but that could fundamentally change the viability of the approach. We present the first MagLIF linear dynamics simulations, using extended magnetohydrodynamical (XMHD) as well as standard MHD modeling, that reproduce these helical structures, thus enabling a physical understanding of their origin and development. Specifically, it is found that low-density plasma from the simulated power flow surfaces can compress the axial flux in the region surrounding the liner, leading to a strong layer of axial flux on the liner. The strong axial magnetic field on the liner imposes helical magneto-Rayleigh-Taylor perturbations into the imploding liner. A detailed comparison of XMHD and MHD modeling shows that there are defects in the MHD treatment of low-density plasma dynamics that are remedied by inclusion of the Hall term that is included in our XMHD model. In order to obtain fair agreement between XMHD and MHD, great care must be taken in the implementation of the numerics, especially for MHD. Even with a careful treatmentmore » of low-density plasma, MHD exhibits significant shortcomings that emphasize the importance of using XMHD modeling in pulsed-power driven high-energy-density experiments. As a result, the present results may explain why past MHD modeling efforts have failed to produce the helical structuring without initially imposing helical perturbations.« less
Authors:
ORCiD logo [1] ;  [2] ;  [1]
  1. Cornell Univ., Ithaca, NY (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND-2018-8579J
Journal ID: ISSN 1070-664X; 666760
Grant/Contract Number:
AC04-94AL85000; FOA-0003764; NA0001836; NA0003525
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 6; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; MagLIF; extended-MHD; Hall effect; simulation; discontinuous Galerkin method
OSTI Identifier:
1464208
Alternate Identifier(s):
OSTI ID: 1456307

Seyler, C. E., Martin, Matthew R., and Hamlin, N. D.. Helical instability in MagLIF due to axial flux compression by low-density plasma. United States: N. p., Web. doi:10.1063/1.5028365.
Seyler, C. E., Martin, Matthew R., & Hamlin, N. D.. Helical instability in MagLIF due to axial flux compression by low-density plasma. United States. doi:10.1063/1.5028365.
Seyler, C. E., Martin, Matthew R., and Hamlin, N. D.. 2018. "Helical instability in MagLIF due to axial flux compression by low-density plasma". United States. doi:10.1063/1.5028365.
@article{osti_1464208,
title = {Helical instability in MagLIF due to axial flux compression by low-density plasma},
author = {Seyler, C. E. and Martin, Matthew R. and Hamlin, N. D.},
abstractNote = {The MagLIF (Magnetized Liner Inertial Fusion) experiment at Sandia National Labs is one of the three main approaches to inertial confinement fusion. Radiographic measurements of the imploding liner have shown helical structuring that was not included in MagLIF scaling calculations but that could fundamentally change the viability of the approach. We present the first MagLIF linear dynamics simulations, using extended magnetohydrodynamical (XMHD) as well as standard MHD modeling, that reproduce these helical structures, thus enabling a physical understanding of their origin and development. Specifically, it is found that low-density plasma from the simulated power flow surfaces can compress the axial flux in the region surrounding the liner, leading to a strong layer of axial flux on the liner. The strong axial magnetic field on the liner imposes helical magneto-Rayleigh-Taylor perturbations into the imploding liner. A detailed comparison of XMHD and MHD modeling shows that there are defects in the MHD treatment of low-density plasma dynamics that are remedied by inclusion of the Hall term that is included in our XMHD model. In order to obtain fair agreement between XMHD and MHD, great care must be taken in the implementation of the numerics, especially for MHD. Even with a careful treatment of low-density plasma, MHD exhibits significant shortcomings that emphasize the importance of using XMHD modeling in pulsed-power driven high-energy-density experiments. As a result, the present results may explain why past MHD modeling efforts have failed to produce the helical structuring without initially imposing helical perturbations.},
doi = {10.1063/1.5028365},
journal = {Physics of Plasmas},
number = 6,
volume = 25,
place = {United States},
year = {2018},
month = {6}
}