100 eV electron temperatures in the Maryland centrifugal experiment observed using electron Bernstein emission

Reid, Remington; Romero-Talamás, C.A.; Young, W. C.; Ellis, R. F.; Hassam, A. B.

doi:10.1063/1.4883499

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…Theoretical models (Mjolsness & Ruppel 1986;Shumlak & Hartman 1995;Shumlak & Roderick 1998;Ruden 2002) and Z-pinch plasma experiments (Shumlak et al 2001) have shown that velocity shear normal to the density gradient at a fluid interface can stabilise RT-driven perturbation growth. Similarly, in centrifugally confined magneticmirror plasma devices, velocity shear in the azimuthal plasma flow has been shown to stabilise the flute instability (Huang & Hassam 2001;Teodorescu et al 2005;Reid et al 2014). In the experiments presented in this work, conservation of angular momentum generates significant velocity shear in the radial direction (∂ω/∂r) at the cavity surface, particularly near turnaround where the cavity surface may be subject to the RT instability.…”

Section: Low-mode-number Experimentsmentioning

confidence: 72%

Rotational stabilisation of the Rayleigh–Taylor instability at the inner surface of an imploding liquid shell

2019

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A number of applications utilise the energy focussing potential of imploding shells to dynamically compress matter or magnetic fields, including magnetised target fusion schemes in which a plasma is compressed by the collapse of a liquid metal surface. This paper examines the effect of fluid rotation on the Rayleigh-Taylor (RT) driven growth of perturbations at the inner surface of an imploding cylindrical liquid shell which compresses a gas-filled cavity. The shell was formed by rotating water such that it was in solid body rotation prior to the piston-driven implosion, which was propelled by a modest external gas pressure. The fast rise in pressure in the gas-filled cavity at the point of maximum convergence results in an RT unstable configuration where the cavity surface accelerates in the direction of the density gradient at the gas-liquid interface. The experimental arrangement allowed for visualization of the cavity surface during the implosion using high-speed videography, while offering the possibility to provide geometrically similar implosions over a wide range of initial angular velocities such that the effect of rotation on the interface stability could be quantified. A model developed for the growth of perturbations on the inner surface of a rotating shell indicated that the RT instability may be suppressed by rotating the liquid shell at a sufficient angular velocity so that the net surface acceleration remains opposite to the interface density gradient throughout the implosion. Rotational stabilisation of highmode-number perturbation growth was examined by collapsing nominally smooth cavities and demonstrating the suppression of small spray-like perturbations that otherwise appear on RT unstable cavity surfaces. Experiments observing the evolution of lowmode-number perturbations, prescribed using a mode-6 obstacle plate, showed that the RT-driven growth was suppressed by rotation, while geometric growth remained present along with significant non-linear distortion of the perturbations near final convergence. †

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Section: Low-mode-number Experimentsmentioning

confidence: 72%

Rotational stabilisation of the Rayleigh–Taylor instability at the inner surface of an imploding liquid shell

2019

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“…Interferometric methods measured densities in the range of m, and thermal electron Bernstein emission provided peak electron temperatures of 100 eV (Reid et al. 2014). Teodorescu et al.…”

Section: Resultsmentioning

confidence: 99%

“…2008; Reid et al. 2014) are from prior experiments, respectively, whereas those for CMFX and Reactor came from MCTrans++ predictive models.…”

Section: Physics Modelmentioning

confidence: 99%

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MCTrans++: a 0-D model for centrifugal mirrors

Schwartz,

Abel,

Hassam

et al. 2024

J. Plasma Phys.

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The centrifugal mirror confinement scheme incorporates supersonic rotation of a plasma into a magnetic mirror device. This concept has been shown experimentally to drastically decrease parallel losses and increase plasma stability as compared with prior axisymmetric mirrors. MCTrans++ is a dimensionless (0-D) scoping tool which rapidly models experimental operating points in the Centrifugal Mirror Fusion Experiment (CMFX) at the University of Maryland. In the low-collisionality regime, parallel losses can be modelled analytically. A confining potential is set up that is partially ambipolar and partially centrifugal. Due to the stabilizing effects of flow shear, the perpendicular losses can be modelled as classical. Radiation losses such as bremsstrahlung and cyclotron emission are taken into account. A neutrals model is included, and, in some circumstances, charge-exchange losses are found to exceed all other loss mechanisms. We use the SUNDIALS ARKODE library to solve the underlying equations of this model; the resulting software is suitable for scanning large parameter spaces, and can also be used to model time-dependent phenomena such as a capacitive discharge. MCTrans++ has been used to verify results from prior centrifugal mirrors, create an experimental plan for CMFX and find configurations for future reactor-scale fusion devices.

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Direct fusion drive based on centrifugal mirror confinement

Carson,

Sedwick

2024

Acta Astronautica

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100 eV electron temperatures in the Maryland centrifugal experiment observed using electron Bernstein emission

Cited by 4 publications

References 14 publications

Rotational stabilisation of the Rayleigh–Taylor instability at the inner surface of an imploding liquid shell

Rotational stabilisation of the Rayleigh–Taylor instability at the inner surface of an imploding liquid shell

MCTrans++: a 0-D model for centrifugal mirrors

Direct fusion drive based on centrifugal mirror confinement

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