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Katz J, Boni R, Milder AL, Nelson D, Daub K, Froula DH. Measurement of Thomson-scattering spectra with continuous angular resolution (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:093513. [PMID: 39240150 DOI: 10.1063/5.0219182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 08/19/2024] [Indexed: 09/07/2024]
Abstract
A novel Thomson-scattering diagnostic with continuous angular resolution over a span of 120° was developed for the characterization of plasmas produced at the Omega Laser Facility. Spectrally resolving light scattered from electron plasma wave features as a function of emission angle provides a means to efficiently probe a large range of plasma frequencies and k vectors. Together, these spectra contain critical constraints on the plasma-physics models used to interpret the data and enable experimental measurements of the electron-velocity distribution function over several orders of magnitude without assumptions about its mathematical form. Major components of the instrument include (1) a reflective collection objective that gathers light over a range of 120° × 12°; (2) a spatial-filter image relay for measurement localization; (3) cylindrical optics for producing a line image of the collection aperture; (4) a transmission grating spectrometer; and (5) a time-gated, image-intensified camera. Thomson-scattered light collected from an ∼50 - μm3 volume of plasma is recorded with 0.8-nm spectral and 1° angular resolution. Initial experiments examined the properties of the electron-velocity distribution in gas-jet-produced plasmas in the presence of heating via inverse bremsstrahlung absorption.
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Affiliation(s)
- J Katz
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - R Boni
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - A L Milder
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - D Nelson
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - K Daub
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - D H Froula
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
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Escalona M, Valenzuela JC, Avaria G, Veloso F, Wyndham ES. Bayesian inference of plasma parameters from collective Thomson scattering technique on a gas-puff near stagnation. Sci Rep 2023; 13:13002. [PMID: 37563239 PMCID: PMC10415259 DOI: 10.1038/s41598-023-40014-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 08/02/2023] [Indexed: 08/12/2023] Open
Abstract
The Collective Thomson scattering technique has been implemented to study the stagnation of a single liner gas-puff. The plasma parameters are determined by theoretically modelling the scattering form factor in combination with Bayesian inference to provide the set of the most probable parameters that describe the experimental data. Analysis of the data reveal that incoming flows are able to interpenetrate partially. Estimation of the mean free path shows a gradual transition from a weakly collisional to a collisional regime as the plasma gets to the axis. Furthermore, we find that the ion energy at [Formula: see text] is [Formula: see text] and is mostly kinetic in nature and represents [Formula: see text] of the total energy. This kinetic energy is far greater than the value on axis of [Formula: see text] which is [Formula: see text] of the total energy. Energy transfer to the electrons and radiation losses are found to be negligible by this time. A possible explanation for this energy imbalance is the presence of an azimuthal magnetic field larger than [Formula: see text] that deflect the ions vertically. The uncertainties quoted represent 68% credible intervals.
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Affiliation(s)
- M Escalona
- Instituto de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Chile
| | - J C Valenzuela
- Instituto de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Chile.
| | - G Avaria
- Research Center on the Intersection in Plasma Physics, Matter and Complexity, P2mc, Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago, Chile
| | - F Veloso
- Instituto de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Chile
| | - E S Wyndham
- Instituto de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Chile
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3
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Valenzuela-Villaseca V, Suttle LG, Suzuki-Vidal F, Halliday JWD, Merlini S, Russell DR, Tubman ER, Hare JD, Chittenden JP, Koepke ME, Blackman EG, Lebedev SV. Characterization of Quasi-Keplerian, Differentially Rotating, Free-Boundary Laboratory Plasmas. PHYSICAL REVIEW LETTERS 2023; 130:195101. [PMID: 37243644 DOI: 10.1103/physrevlett.130.195101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/29/2023] [Indexed: 05/29/2023]
Abstract
We present results from pulsed-power driven differentially rotating plasma experiments designed to simulate physics relevant to astrophysical disks and jets. In these experiments, angular momentum is injected by the ram pressure of the ablation flows from a wire array Z pinch. In contrast to previous liquid metal and plasma experiments, rotation is not driven by boundary forces. Axial pressure gradients launch a rotating plasma jet upward, which is confined by a combination of ram, thermal, and magnetic pressure of a surrounding plasma halo. The jet has subsonic rotation, with a maximum rotation velocity 23±3 km/s. The rotational velocity profile is quasi-Keplerian with a positive Rayleigh discriminant κ^{2}∝r^{-2.8±0.8} rad^{2}/s^{2}. The plasma completes 0.5-2 full rotations in the experimental time frame (∼150 ns).
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Affiliation(s)
| | - L G Suttle
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - F Suzuki-Vidal
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - J W D Halliday
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - S Merlini
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - D R Russell
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - E R Tubman
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - J D Hare
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - J P Chittenden
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - M E Koepke
- Department of Physics, West Virginia University, Morgantown, West Virginia 26506, USA
| | - E G Blackman
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - S V Lebedev
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
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Russell DR, Burdiak GC, Carroll-Nellenback JJ, Halliday JWD, Hare JD, Merlini S, Suttle LG, Valenzuela-Villaseca V, Eardley SJ, Fullalove JA, Rowland GC, Smith RA, Frank A, Hartigan P, Velikovich AL, Chittenden JP, Lebedev SV. Perpendicular Subcritical Shock Structure in a Collisional Plasma Experiment. PHYSICAL REVIEW LETTERS 2022; 129:225001. [PMID: 36493430 DOI: 10.1103/physrevlett.129.225001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 10/14/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
We present a study of perpendicular subcritical shocks in a collisional laboratory plasma. Shocks are produced by placing obstacles into the supermagnetosonic outflow from an inverse wire array z pinch. We demonstrate the existence of subcritical shocks in this regime and find that secondary shocks form in the downstream. Detailed measurements of the subcritical shock structure confirm the absence of a hydrodynamic jump. We calculate the classical (Spitzer) resistive diffusion length and show that it is approximately equal to the shock width. We measure little heating across the shock (<10% of the ion kinetic energy) which is consistent with an absence of viscous dissipation.
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Affiliation(s)
- D R Russell
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - G C Burdiak
- First Light Fusion Ltd, Yarnton, Kidlington OX5 1QU, United Kingdom
| | - J J Carroll-Nellenback
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - J W D Halliday
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - J D Hare
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S Merlini
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - L G Suttle
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | | | - S J Eardley
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - J A Fullalove
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - G C Rowland
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - R A Smith
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - A Frank
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - P Hartigan
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005-1892, USA
| | - A L Velikovich
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - J P Chittenden
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - S V Lebedev
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
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Datta R, Russell DR, Tang I, Clayson T, Suttle LG, Chittenden JP, Lebedev SV, Hare JD. Time-resolved velocity and ion sound speed measurements from simultaneous bow shock imaging and inductive probe measurements. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:103530. [PMID: 36319372 DOI: 10.1063/5.0098823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/01/2022] [Indexed: 06/16/2023]
Abstract
We present a technique to measure the time-resolved velocity and ion sound speed in magnetized, supersonic high-energy-density plasmas. We place an inductive ("b-dot") probe in a supersonic pulsed-power-driven plasma flow and measure the magnetic field advected by the plasma. As the magnetic Reynolds number is large (RM > 10), the plasma flow advects a magnetic field proportional to the current at the load. This enables us to estimate the flow velocity as a function of time from the delay between the current at the load and the signal at the probe. The supersonic flow also generates a hydrodynamic bow shock around the probe, the structure of which depends on the upstream sonic Mach number. By imaging the shock around the probe with a Mach-Zehnder interferometer, we determine the upstream Mach number from the shock Mach angle, which we then use to determine the ion sound speed from the known upstream velocity. We use the sound speed to infer the value of Z̄Te, where Z̄ is the average ionization and Te is the electron temperature. We use this diagnostic to measure the time-resolved velocity and sound speed of a supersonic (MS ∼ 8), super-Alfvénic (MA ∼ 2) aluminum plasma generated during the ablation stage of an exploding wire array on the Magpie generator (1.4 MA, 250 ns). The velocity and Z̄Te measurements agree well with the optical Thompson scattering measurements reported in the literature and with 3D resistive magnetohydrodynamic simulations in GORGON.
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Affiliation(s)
- R Datta
- Plasma Science & Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - D R Russell
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - I Tang
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - T Clayson
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - L G Suttle
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - J P Chittenden
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - S V Lebedev
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - J D Hare
- Plasma Science & Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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