Structure and Dynamics of Magneto-Inertial, Differentially Rotating Laboratory Plasmas

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Main Authors: Valenzuela-Villaseca, V., Suttle, L. G., Suzuki-Vidal, F., Halliday, J. W. D., Russell, D. R., Merlini, S., Tubman, E. R., Hare, J. D., Chittenden, J. P., Koepke, M. E., Blackman, E. G., Lebedev, S. V.
Format: Preprint
Published: 2024
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author Valenzuela-Villaseca, V.
Suttle, L. G.
Suzuki-Vidal, F.
Halliday, J. W. D.
Russell, D. R.
Merlini, S.
Tubman, E. R.
Hare, J. D.
Chittenden, J. P.
Koepke, M. E.
Blackman, E. G.
Lebedev, S. V.
author_facet Valenzuela-Villaseca, V.
Suttle, L. G.
Suzuki-Vidal, F.
Halliday, J. W. D.
Russell, D. R.
Merlini, S.
Tubman, E. R.
Hare, J. D.
Chittenden, J. P.
Koepke, M. E.
Blackman, E. G.
Lebedev, S. V.
contents We present a detailed characterization of the structure and evolution of differentially rotating plasmas driven on the MAGPIE pulsed-power generator (1.4 MA peak current, 240 ns rise-time). The experiments were designed to simulate physics relevant to accretion discs and jets on laboratory scales. A cylindrical aluminium wire array Z pinch enclosed by return posts with an overall azimuthal off-set angle was driven to produce ablation plasma flows that propagate inwards in a slightly off-radial trajectory, injecting mass, angular momentum, and confining ram pressure to a rotating plasma column on the axis. However, the plasma is free to expand axially, forming a collimated, differentially rotating axial jet that propagates at $\approx 100$ km/s. The density profile of the jet corresponds to a dense shell surrounding a low-density core, which is consistent with the centrifugal barrier effect being sustained along the jet's propagation. We show analytically that, as the rotating plasma accretes mass, conservation of mass and momentum implies plasma radial growth scaling as $r \propto t^{1/3}$. As the characteristic moment of inertia increases, the rotation velocity is predicted to decrease and settle on a characteristic value $\approx 20$ km/s. We find that both predictions are in agreement with Thomson scattering and optical self-emission imaging measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2403_20321
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Structure and Dynamics of Magneto-Inertial, Differentially Rotating Laboratory Plasmas
Valenzuela-Villaseca, V.
Suttle, L. G.
Suzuki-Vidal, F.
Halliday, J. W. D.
Russell, D. R.
Merlini, S.
Tubman, E. R.
Hare, J. D.
Chittenden, J. P.
Koepke, M. E.
Blackman, E. G.
Lebedev, S. V.
Plasma Physics
High Energy Astrophysical Phenomena
We present a detailed characterization of the structure and evolution of differentially rotating plasmas driven on the MAGPIE pulsed-power generator (1.4 MA peak current, 240 ns rise-time). The experiments were designed to simulate physics relevant to accretion discs and jets on laboratory scales. A cylindrical aluminium wire array Z pinch enclosed by return posts with an overall azimuthal off-set angle was driven to produce ablation plasma flows that propagate inwards in a slightly off-radial trajectory, injecting mass, angular momentum, and confining ram pressure to a rotating plasma column on the axis. However, the plasma is free to expand axially, forming a collimated, differentially rotating axial jet that propagates at $\approx 100$ km/s. The density profile of the jet corresponds to a dense shell surrounding a low-density core, which is consistent with the centrifugal barrier effect being sustained along the jet's propagation. We show analytically that, as the rotating plasma accretes mass, conservation of mass and momentum implies plasma radial growth scaling as $r \propto t^{1/3}$. As the characteristic moment of inertia increases, the rotation velocity is predicted to decrease and settle on a characteristic value $\approx 20$ km/s. We find that both predictions are in agreement with Thomson scattering and optical self-emission imaging measurements.
title Structure and Dynamics of Magneto-Inertial, Differentially Rotating Laboratory Plasmas
topic Plasma Physics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2403.20321