Trevor Hutchinson

On the Evolution From Micrometer-Scale Inhomogeneity to Global Overheated Structure During the Intense Joule Heating of a z-Pinch Rod

Ultrafast optical microscopy of metal z-pinch rods pulsed with megaampere current is contributing new data and critical insight into what provides the fundamental seed for the magneto-Rayleigh–Taylor (MRT) instability. A two-frame near infrared/visible intensified-charge-coupled device gated imager with 2-ns temporal resolution and 3-<inline-formula> <tex-math notation=LaTeX>

Megagauss-level magnetic field production in cm-scale auto-magnetizing helical liners pulsed to 500 kA in 125 ns

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Zピンチロッドの強いジュール加熱中のマイクロメータスケール不均一性大域的過熱した構造まで進化について【Powered by NICT】

</tex-math></inline-formula> spatial resolution captured emissions from the nonuniformly Joule heated surfaces of ultrasmooth aluminum (Al) rods. Nonuniform surface emissions are consistently first observed from discrete, 10-<inline-formula> <tex-math notation=LaTeX>

Experimental Study of Magnetic Field Production and Dielectric Breakdown of Auto-Magnetizing Liners

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Experimental Observation of the Stratified Electrothermal Instability on Dielectric-Coated Thick Aluminum

</tex-math></inline-formula> scale, subelectronvolt spots. Aluminum 6061 alloy, with micrometer-scale nonmetallic resistive inclusions, forms several times more spots than 99.999% pure Al 5N; 5–10 ns later, azimuthally stretched elliptical spots and distinct strata (40–100 <inline-formula> <tex-math notation=LaTeX>

Spectral Dependence of Stratified Electrothermal Instability in Tamped Aluminum 6061 with Current in a Skin Layer

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Nano-Surface Finishing for Electrothermal Instability Evolution Studies

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Difference in Magnetic Field Threshold for Thermal Plasma Formation between Copper Alloys 145 and 101 Pulsed to Multi-Megagauss Surface Magnetic Field

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Observations of ETI under dielectric-overcoated aluminum pulsed to hundreds of Tesla

</tex-math></inline-formula> tall) are observed on Al 6061, but not on Al 5N. Such overheat strata, which are aligned parallel to the magnetic field, are highly effective seeds for MRT instability growth. These data give credence to the hypothesis that early nonuniform Joule heating, such as the electrothermal instability, may provide the dominant seed for MRT.

Development of the electrothermal instability from resistive inclusions

Auto-magnetizing (AutoMag) liners [Slutz et al., Phys. Plasmas 24, 012704 (2017)] are designed to generate up to 100u2009T of axial magnetic field in the fuel for Magnetized Liner Inertial Fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010)] without the need for external field coils. AutoMag liners (cylindrical tubes) are composed of discrete metallic helical conduction paths separated by electrically insulating material. Initially, helical current in the AutoMag liner produces internal axial magnetic field during a long (100 to 300u2009ns) current prepulse with an average current rise rate d I / d t = 5 k A / n s. After the cold fuel is magnetized, a rapidly rising current ( 200 k A / n s) generates a calculated electric field of 64 M V / m between the helices. Such field is sufficient to force dielectric breakdown of the insulating material after which liner current is reoriented from helical to predominantly axial which ceases the AutoMag axial magnetic field production mechanism and the z-pinch liner ...