Enhanced energy coupling for indirectly driven inertial confinement fusion

Ping, Yuan; Smalyuk, V. A.; Amendt, Peter; Tommasini, R.; Field, J. E.; Khan, S. F.; Bennett, Don; Dewald, E. L.; Graziani, Frank; Johnson, S.; Landen, O. L.; MacPhee, A. G.; Nikroo, A.; Pino, Jesse; Prisbrey, Shon; Ralph, J. E.; Seugling, R M; Strozzi, D. J.; Tipton, Robert; Wang, Y. M.; Loomis, Eric; Merritt, E. C.; Montgomery, David

doi:10.1038/s41567-018-0331-5

Cited by 37 publications

(20 citation statements)

References 30 publications

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“…Further, recent experiments [5] on the NIF showed that the fusion energy was enhanced to 54 kJ, corresponding, however, to a gain factor Q of only about 0.03. Therefore, there is a long way to achieve ignition of the fusion reaction, mainly due to the low energy coupling efficiency of the laser-produced X-rays with the fuel as well as other technological difficulties [7]. On the other hand, the direct-drive central ignition scheme can obtain much higher energy coupling efficiency [8].…”

Section: Introductionmentioning

confidence: 99%

Double-cone ignition scheme for inertial confinement fusion

Zhang

Wang

Yang

et al. 2020

Phil. Trans. R. Soc. A.

101

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While major progress has been made in the research of inertial confinement fusion, significant challenges remain in the pursuit of ignition. To tackle the challenges, we propose a double-cone ignition (DCI) scheme, in which two head-on gold cones are used to confine deuterium–tritium (DT) shells imploded by high-power laser pulses. The scheme is composed of four progressive controllable processes: quasi-isentropic compression, acceleration, head-on collision and fast heating of the compressed fuel. The quasi-isentropic compression is performed inside two head-on cones. At the later stage of the compression, the DT shells in the cones are accelerated to forward velocities of hundreds of km s –1 . The head-on collision of the compressed and accelerated fuels from the cone tips transfer the forward kinetic energy to the thermal energy of the colliding fuel with an increased density. The preheated high-density fuel can keep its status for a period of approximately 200 ps. Within this period, MeV electrons generated by ps heating laser pulses, guided by a ns laser-produced strong magnetic field further heat the fuel efficiently. Our simulations show that the implosion inside the head-on cones can greatly mitigate the energy requirement for compression; the collision can preheat the compressed fuel of approximately 300 g cm −3 to a temperature above keV. The fuel can then reach an ignition temperature of greater than 5 keV with magnetically assisted heating of MeV electrons generated by the heating laser pulses. Experimental campaigns to demonstrate the scheme have already begun. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 1)’.

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Section: Introductionmentioning

confidence: 99%

Double-cone ignition scheme for inertial confinement fusion

Zhang

Wang

Yang

et al. 2020

Phil. Trans. R. Soc. A.

101

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“…Possible experiments on inter-atomic Kα emissions. Experimental verification of these first-principles predictions of interatomic Kα emissions can possibly be conducted at the Omega Laser Facility utilizing the platform of double-shell implosions 14,15,42,43 . In a double-shell target, the inner metal shell can be made of mid-Z Fe-Cu or Fe-Zn alloys with a core of D2-gas fill.…”

Section: Density Dependence Of Interspecies Radiative Transition (Irt)mentioning

confidence: 95%

“…For instance, deuterium and tritium contained in a millimeter-size inertial confinement fusion (ICF) target can be squeezed to ρ = 10 2 -10 3 g cm −3 by powerful lasers through laserdriven compression and spherical convergence [9][10][11][12][13] . Using doubleshell implosions 14,15 , mid-/high-Z materials can be squeezed to super-high densities ranging from ρ = 10 3 -10 4 g cm −3 with a temperature ranging from tens to hundreds of electron volts (1 eV~11,604 K). Understanding how matter behaves at such extreme conditions is the purview of high-energy-density physics, inertial confinement fusion, planetary science, and astrophysics.…”

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confidence: 99%

Interspecies radiative transition in warm and superdense plasma mixtures

Karasiev

Recoules

et al. 2020

Nat Commun

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Superdense plasmas widely exist in planetary interiors and astrophysical objects such as brown-dwarf cores and white dwarfs. How atoms behave under such extreme-density conditions is not yet well understood, even in single-species plasmas. Here, we apply thermal density functional theory to investigate the radiation spectra of superdense iron-zinc plasma mixtures at mass densities of ρ = 250 to 2000 g cm −3 and temperatures of kT = 50 to 100 eV, accessible by double-shell-target implosions. Our ab initio calculations reveal two extreme atomic-physics phenomena-firstly, an interspecies radiative transition; and, secondly, the breaking down of the dipole-selection rule for radiative transitions in isolated atoms. Our first-principles calculations predict that for superdense plasma mixtures, both interatomic radiative transitions and dipole-forbidden transitions can become comparable to the normal intra-atomic Kα-emission signal. These physics phenomena were not previously considered in detail for extreme high-density plasma mixtures at super-high energy densities.

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“…While beryllium capsules have been considered for many years as a leading candidate for indirect-drive ignition [122,123], few experiments using Be capsules have been performed [96,124]. Indirect-drive experiments using aluminum outer shells are now fielded routinely at NIF for double-shell highyield concepts [125][126][127]. Aluminum shells are not appropriate for Omega because of their higher mass and because they would have to be filled with a fill tube-a capability not available at Omega.…”

Section: 2 Metal Capsulesmentioning

confidence: 99%

Effect of Impurity Atoms on Thermonuclear Yield

Batha

2020

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The presence of impurity atoms in an inertial confinement fusion (ICF) implosion can greatly affect the burning of the thermonuclear fuel. This is a serious concern for attaining ignition as high atomic number atoms, such as carbon, can mix into the hot spot and reach the deuterium-tritium (DT) fuel, absorb energy from the implosion, and radiate away that energy. The temperature of the DT fuel drops and reduces the reactivity of the fuel resulting in lower thermonuclear yield. Fuel impurities can also be a useful diagnostic as when higher-Z atoms, such as Ar, Kr, and Xe, are purposefully mixed into the fuel. From the spectra emitted by these atoms, the temperature and density of the fuel can be deduced. The long history of using such tracer atoms by the national ICF program shows the great advances in experimental technique, diagnostic instruments, and atomic-physics modeling over the past 50 years. A particular set of experiments, the "High-Z" campaign, is reviewed in depth as this was the most systematic study of tracer element composition and quantity ever reported. Difficulties in interpreting the results of those experiments due to the limited code capabilities at that time are discussed. A main concern for the High-Z campaign was the then current state of non-Local Thermodynamic Equilibrium (nLTE) atomic physics models. The present state of nLTE modeling and its implementation in Los Alamos's multi-physics codes is discussed in this report. To further the understanding of the complex interaction of high-Z atoms in the gas, a survey of relevant existing experimental platforms at the National Ignition Facility (NIF) and the Omega Laser Facility are presented along with the current state of pertinent diagnostics at NIF and Omega. This review concludes with a discussion of the trade-off available between temperature and volume of the imploded ICF capsule with the goal of maximizing the total yield. 10 24 cm•3 3 x 10 23 cm•3

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Enhanced energy coupling for indirectly driven inertial confinement fusion

Cited by 37 publications

References 30 publications

Double-cone ignition scheme for inertial confinement fusion

Double-cone ignition scheme for inertial confinement fusion

Interspecies radiative transition in warm and superdense plasma mixtures

Effect of Impurity Atoms on Thermonuclear Yield

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