Imploding Liner Compression of Plasma: Concepts and Issues

Turchi, P. J.

doi:10.1109/tps.2007.914173

Cited by 25 publications

(7 citation statements)

References 23 publications

(30 reference statements)

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“…The influence of the Rayleigh-Taylor instability on implosion phenomena is of relevance to a number of scientific and engineering applications, including Z -pinch devices (Golberg & Velikovich 1993;Velikovich et al 1996;Ryutov et al 2000), laser-driven inertial confinement fusion (Hsing et al 1997;Mikaelian 2010;Velikovich & Schmit 2015), and magnetic flux compression (Harris 1962;Somon 1969;Buyko et al 1997). Of particular interest for the present work is a magnetised target fusion (MTF) (Kirkpatrick et al 1995;Buyko et al 1997) concept in which a plasma target is compressed by an imploding liquid metal surface to reach fusion conditions (Laberge 2008;Turchi 2008;Suponitsky et al 2014). In this concept, which was initially proposed during the LINUS program (Turchi et al 1980;Robson 1982), a cylindrical or spherical rotating liquid shell is collapsed by mechanical pistons in a quasi-reversible cycle in order to compress the plasma to fusion conditions.…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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

2019

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“…This inspired the Linus project at the Naval Research Laboratory [25], and later the fast-liner project at Los Alamos [26]. In Russia, MIF took a form called magnitnoye obzhatiye, or magnetic compression (MAGO), first revealed by Russian scientists when the Cold War ended [27][28][29], and worked on collaboratively with experiments at LANL [30]. Presently the USA clearly holds world leadership in MIF research, but fledgling MIF efforts are also underway in China and France.…”

Section: Statusmentioning

confidence: 99%

Magneto-Inertial Fusion

et al. 2015

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In this community white paper, we describe an approach to achieving fusion which employs a hybrid of elements from the traditional magnetic and inertial fusion concepts, called magneto-inertial fusion (MIF). The status of MIF research in North America at multiple institutions is summarized including recent progress, research opportunities, and future plans.Keywords Magneto-inertial fusion Á Magnetized target fusion Á Liner Á Plasma jets Á Fusion energy Á MagLIF DescriptionMagneto-inertial fusion (MIF) (aka magnetized target fusion) [1][2][3] is an approach to fusion that combines the compressional heating of inertial confinement fusion (ICF) with the magnetically reduced thermal transport and magnetically enhanced alpha heating of magnetic confinement fusion (MCF). From an MCF perspective, the higher density, shorter confinement times, and compressional heating as the dominant heating mechanism reduce the impact of instabilities. From an ICF perspective, the primary benefits are potentially orders of magnitude reduction in the difficult to achieve qr parameter (areal density), and potentially significant reduction in velocity requirements and hydrodynamic instabilities for compression drivers. In fact, ignition becomes theoretically possible from qr B 0.01 g/cm 2 up to conventional ICF values of qr * 1.0 g/cm 2 , and as in MCF, Br rather than qr becomes the key figure-of-merit for ignition because of the enhanced alpha deposition [4]. Within the lower-qr parameter space, MIF exploits lower required implosion velocities (2-100 km/s, compared to the ICF minimum of 350-400 km/s) allowing the use of much more efficient (g C 0.3) pulsed power drivers, while at the highest (i.e., ICF) end of the qr range, both higher gain G at a given implosion velocity as well as lower implosion velocity and reduced hydrodynamic instabilities are theoretically possible. To avoid confusion, it must be emphasized that the wellknown conventional ICF burn fraction formula does not apply for the lower-qr ''liner-driven'' MIF schemes, since it is the much larger mass and qr of the liner (and not that of the burning fuel) that determines the ''dwell time'' and fuel burnup fraction. In all cases, MIF approaches seek to satisfy/ exceed the inertial fusion energy (IFE) figure-of-merit gG * 7-10 required in an economical plant with reasonable recirculating power fraction. A great advantage of MIF is indeed its extremely wide parameter space which allows it greater versatility in overcoming difficulties in implementation or technology, as evidenced by the four diverse approaches and associated implosion velocities shown in Fig. 1.MIF approaches occupy an attractive region in thermonuclear q-T parameter space, as shown in a paper by

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“…The plasma and metal loads are imploded by the azimuthal magnetic field of the axial current passed through the load. In many cases, an external axial magnetic field is applied to stabilize the implosion or provide the 'magneto-thermo-insulation' (Lindemuth & Kirkpatrick 1983) of the stagnated plasma, which is the critical issue for all approaches to magnetized target fusion and magneto-inertial fusion (Turchi 2008;Garanin 2013;Wurden et al 2016;Lindemuth 2017), including the MagLIF. The axial magnetic field, in turn, can affect the implosion dynamics in various ways, not all of which are fully understood; see Felber et al (1988), Shishlov et al (2006), Rousskikh et al (2017), Mikitchuk et al (2019), Conti et al (2020), Seyler (2020) and references therein.…”

Section: Introductionmentioning

confidence: 99%

Stable and unstable supersonic stagnation of an axisymmetric rotating magnetized plasma

et al. 2022

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The Naval Research Laboratory ‘Mag Noh problem’, described in this paper, is a self-similar magnetized implosion flow, which contains a fast magnetohydrodynamic (MHD) outward propagating shock of constant velocity. We generalize the classic Noh (OSTI Tech. Rep. 577058, 1983) problem to include azimuthal and axial magnetic fields as well as rotation. Our family of ideal MHD solutions is five parametric, each solution having its own self-similarity index, gas gamma, magnetization, the ratio of axial to the azimuthal field and rotation. While the classic Noh problem must have a supersonic implosion velocity to create a shock, our solutions have an interesting three-parametric special case with zero initial velocity in which magnetic tension, instead of implosion flow, creates the shock at $t=0+$ . Our self-similar solutions are indeed realized when we solve the initial value MHD problem with the finite volume MHD code Athena. We numerically investigated the stability of these solutions and found both stable and unstable regions in parameter space. Stable solutions can be used to test the accuracy of numerical codes. Unstable solutions have also been widely used to test how codes reproduce linear growth, transition to turbulence and the practically important effects of mixing. Now we offer a family of unstable solutions featuring all three elements relevant to magnetically driven implosions: convergent flow, magnetic field and a shock wave.

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Imploding Liner Compression of Plasma: Concepts and Issues

Cited by 25 publications

References 23 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

Magneto-Inertial Fusion

Stable and unstable supersonic stagnation of an axisymmetric rotating magnetized plasma

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