Magneto-inertial Approach to Direct-drive Laser Fusion

Gotchev, O. V.; Jang, N. W.; Knauer, J. P.; Barbero, M. D.; Betti, R.; Li, C. K.; Petrasso, R. D.

doi:10.1007/s10894-007-9112-3

Cited by 33 publications

(28 citation statements)

References 16 publications

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“…[3][4][5][6][7][8][9][10][11][12][13] The magnetothermal instability is driven by collisional transport phenomena alone and therefore of particular interest because it acts to destabilise plasmas in the absence of more usual mechanisms. In particular, unstable growth results from coupling between (i) the Nernst effect, that is, advection of B with the diffusive heat-flow q ?…”

Section: -13mentioning

confidence: 99%

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Magnetothermal instability in laser plasmas including hydrodynamic effects

2012

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Lett. 98, 135001 (2007)] and shown to be in good agreement: exhibiting peak growth-rates and wavelengths of order 10 ns 1 and 50 lm, respectively. The instability's relevance to other experimental conditions, including those in inertial confinement fusion (I.C.F.) hohlraums, is also discussed.

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Section: -13mentioning

confidence: 99%

“…[3][4][5] and magneto-inertial fusion (M.I.F.) [6][7][8] schemes but also for more general experimental topics, such as the suppression of heat transport, 9 the control of density channels, 10 and the evolution of plasma bubbles.…”

Section: Introductionmentioning

confidence: 99%

Magnetothermal instability in laser plasmas including hydrodynamic effects

2012

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“…The results from the first experiments on a new approach that provides very effective flux compression are reported here. The field is compressed by the ablative pressure exerted on an imploding ICF capsule by the driving laser [10]. This approach was proposed in the 1980s [11] as a way to achieve record compressed fields with possible applications for fusion [12] but no laser experiments were performed.…”

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confidence: 99%

“…Some of the physical details of this concept are described in Ref. [10]. The shock-heated D 2 fuel traps the seed magnetic field, which would otherwise diffuse much faster through the relatively cold (resistive) imploding shell.…”

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Laser-Driven Magnetic-Flux Compression in High-Energy-Density Plasmas

et al. 2009

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The demonstration of magnetic field compression to many tens of megagauss in cylindrical implosions of inertial confinement fusion targets is reported for the first time. The OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] was used to implode cylindrical CH targets filled with deuterium gas and seeded with a strong external field (>50 kG) from a specially developed magnetic pulse generator. This seed field was trapped (frozen) in the shock-heated gas fill and compressed by the imploding shell at a high implosion velocity, minimizing the effect of resistive flux diffusion. The magnetic fields in the compressed core were probed via proton deflectrometry using the fusion products from an imploding D 3 He target. Line-averaged magnetic fields between 30 and 40 MG were observed. In the magnetic fusion energy (MFE) concept, a strong magnetic field confines the plasma and reduces the electron thermal conduction to the vessel wall [1]. The magnetic pressure of typical $0:1-MG fields is higher than the total energy density of the plasma (with ¼ 2 0 p=B 2 < 1). MFE plasmas are fully magnetized and characterized by a Hall parameter ! ce > 1 since the modest gyrofrequency ! ce is matched by long collision times . In contrast, typical inertial confinement fusion (ICF) plasmas have collision frequencies higher by 10 to 12 orders of magnitude because of their extreme density. In such systems, thermal conduction losses are a major factor in the energy balance of an implosion. While it can be more difficult, magnetizing the hot spot in ICF implosions can lead to improved gains and to a reduction of the energy required for ignition. A similar approach is used in the magnetized target fusion concept [2], where the fusion burn requires relatively low-implosion velocities, provided there is an adequate magnetic thermal insulation. In ICF implosions, lower implosion velocities lead to higher gains [3]. However, tens of MG are needed to achieve ! ce $ 1 in the hot spot of a typical, direct drive DT ignition target [4] with hot-spot density of $30 g=cc and a temperature of $7 keV. Such a field is higher than both the self-generated magnetic fields (see Ref. [5]) and the external fields that can be generated by coils. Magnetic-flux compression [6] is a viable path to generating tens of MG magnetic fields with adequate size compression of a metal liner driven by high explosives [7,8] or by pulsed power. The latter approach has been pursued by the Z-pinch [9] communities. The results from the first experiments on a new approach that provides very effective flux compression are reported here. The field is compressed by the ablative pressure exerted on an imploding ICF capsule by the driving laser [10]. This approach was proposed in the 1980s [11] as a way to achieve record compressed fields with possible applications for fusion [12] but no laser experiments were performed. There are numerous advantages to this approach as the implosion velocity is high (a few 10 7 cm=s) and the hot plasma is an effective conductor that tra...

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“…The University of Rochester has introduced seed magnetic fields into the center of targets at the OMEGA laser facility, and compressed those fields by imploding a liner with the OMEGA laser. They have obtained record values of magnetic field and demonstrated increases in neutron yields [8][9][10]. Sandia is developing magnetized liner inertial fusion (MagLIF), in which a magnetically driven beryllium liner, imploded by the Z-machine, adiabatically compresses a laser-preheated magnetized DT target plasma [11][12][13][14].…”

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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Magneto-inertial Approach to Direct-drive Laser Fusion

Cited by 33 publications

References 16 publications

Magnetothermal instability in laser plasmas including hydrodynamic effects

Magnetothermal instability in laser plasmas including hydrodynamic effects

Laser-Driven Magnetic-Flux Compression in High-Energy-Density Plasmas

Magneto-Inertial Fusion

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