Time-resolved velocity and ion sound speed measurements from simultaneous bow shock imaging and inductive probe measurements
Name
5.0098823.pdf
Description
Published version
Size
5.28 MB
Format
Adobe PDF
Checksum (MD5)
47f3e54dc6dd7efe483ed8c899900103
Author(s)
Datta, R
Russell, DR
Tang, I
Clayson, T
Suttle, LG
Chittenden, JP
Lebedev, SV
Hare, JD
Date Issued
October 1, 2022
Journal
Review of Scientific Instruments
Publisher
AIP Publishing
Citation
Datta, R, Russell, DR, Tang, I, Clayson, T, Suttle, LG et al. 2022. "Time-resolved velocity and ion sound speed measurements from simultaneous bow shock imaging and inductive probe measurements." Review of Scientific Instruments, 93 (10).
Version
Final published version
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 ( R M > 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 [Formula: see text], where [Formula: see text] is the average ionization and T e is the electron temperature. We use this diagnostic to measure the time-resolved velocity and sound speed of a supersonic ( M S ∼ 8), super-Alfvénic ( M A ∼ 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 [Formula: see text] measurements agree well with the optical Thompson scattering measurements reported in the literature and with 3D resistive magnetohydrodynamic simulations in GORGON.
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Terms of Use
Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.1063/5.0098823
