Scaling laws for the ignition of deuterium—tritium shell targets

Plriz, A.R.

doi:10.1016/s0920-3796(96)00516-9

Cited by 5 publications

(4 citation statements)

References 18 publications

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“…[7] it was shown that the dynamic effect of a scale dependent time of inertial confinement, in combination with a more realistic pressure profile, reduces the value of the exponent b from 10 to 7. Piriz [8] applied analytical methods to treat the dynamics of ignition profile formation under the influence of heat conduction and α particle transport and obtained E ig ∝ v −5 im . His result seemed to corroborate the conclusion of Ref.…”

Section: Introductionmentioning

confidence: 99%

Ignition energy scaling of inertial confinement fusion targets

Basko

Johner

1998

Nucl. Fusion

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ABSTRACT. Scaling of the ignition energy threshold Eig with the implosion velocity vim and isentrope parameter α of imploding spherical DT shells is investigated by performing one dimensional (1-D) hydrodynamic simulations of the implosion and hot spot formation dynamics. It is found that the a and b exponents in the power law approximation Eig ∝ α a v −b im depend crucially on the subset of initial configurations chosen to establish the scaling law. When the initial states are generated in the same way as in the Livermore study (W.K. Levedahl, J.D. Lindl, Nucl. Fusion 37 (1997) 165), the same scaling, Eig ∝ α 1.7 v −5.5 im , is recovered. If, however, the initial states are generated by rescaling the parent configuration according to the hydrodynamic similarity laws, a different scaling is obtained, Eig ∝ α 3.0 v −9.1 im , which is very close to the α 3 v −10 im dependence predicted by the simple isobaric model for assembled fuel states. The latter is more favourable than the Livermore scaling when rescaling the fusion capsules to higher implosion velocities, but requires the peak drive pressure to be increased as P ∝ v 5 im .

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Section: Introductionmentioning

confidence: 99%

Ignition energy scaling of inertial confinement fusion targets

Basko

Johner

1998

Nucl. Fusion

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“…Past works [97,106,[111][112][113][114][115][116][117][118] have given scaling laws relating the minimum kinetic energy required for isobaric selfignition to the implosion velocity v, the shell adiabat a,/, and the peak ablation pressure p a applied at the end of the acceleration stage. An exhaustive description of different scaling is done in [97] where discrepancy is highlighted between models and numerical fits concerning the ignition criteria: J s = (gR)hTh = const or J s a v. The self-consistent model developed in [97] integrating the return shock propagation in the shell and the change of shell adiabat at stagnation leads to the following minimum kinetic energy scaling for ignition: 39 , similar to the one used in recent literature [119] and proposed by Hermann etal [117]: E Kmin a v -5.89±o.i2 a i.88±o.o5 p -o.77±o.i2_ Inthese scalings, ignition is not occurring at the same energy than Ek^ but when target gain G = £xh/-Et.min = 1 (G is defined as the ratio of the capsule thermonuclear yield £xh over the capsule absorbed energy E^mm), achieved at lower kinetic energy than Ek,ihr-Thus, figure 13 compares these energies for both A.…”

Section: Kinetic Energy Thresholdsmentioning

confidence: 99%

Section: Kinetic Energy Thresholdsmentioning

confidence: 99%

Low initial aspect-ratio direct-drive target designs for shock- or self-ignition in the context of the laser Megajoule

et al. 2014

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Analysis of low initial aspect ratio direct-drive target designs is carried out by varying the implosion velocity and the fuel mass. Starting from two different spherical targets with a given 300 /xg-DT mass, optimization of laser pulse and drive power allows to obtain a set of target seeds referenced by their peak implosion velocities and initial aspect ratio (A = 3 and A = 5). Self-ignition is achieved with higher implosion velocity for A = 5-design than for A = 3-design. Then, rescaling is done to extend the set of designs to a huge amount of mass, peak kinetic energies and peak areal densities. Self-ignition kinetic energy threshold Ek is characterized by a dependance of Ek ~ v& with ^S-values which depart from self-ignition models. Nevertheless, self-ignition energy is seen lower for smaller initial aspect ratio. An analysis of Two-Plasmons Decay threshold and Rayleigh-Taylor instability e-folding is carried out and it is shown that two-plasmon decay threshold is always overpassed for all designs. The hydrodynamic stability analysis is performed by embedded models to deal with linear and non-linear regime. It is found that the A = 5-designs are always at the limit of disruption of the shell.

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“…It is usual to show the necessary ignition condition in IFE by plotting the criteria for hotspot ignition in a domain of ρr versus T (or Wheeler plot) [27][28][29][30][31][32]. Here ρ is the mass density, r the radius (so r hs is the hot-spot radius).…”

Section: 21mentioning

confidence: 99%

Issues for magnetic and inertial fusion energy development

Wootton¹,

Perkins²

2000

Plasma Phys. Control. Fusion

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A discussion of the issues facing both magnetic and inertial fusion schemes for the generation of energy is presented. For magnetic fusion, the conventional tokamak device appears likely to 'work', i.e. it will convert wall plug power into plasma temperature and reasonable energy gain will be obtained. However, it is viewed by many as unacceptable as a commercial reactor candidate-i.e. it is too expensive and too complex. Arguing that within a given concept (but not between concepts) compactness is advantageous, a steady-state energy balance model is used to illustrate how to reduce size. Inertial fusion offers potential advantages over its magnetic counterpart, but while physics progress has been maintained, hot-spot ignition and propagating burn remain to be demonstrated in the laboratory. The proposed solutions to inertial fusion technology challenges, mostly very different from those involved in magnetic fusion, also require demonstrating.

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Scaling laws for the ignition of deuterium—tritium shell targets

Cited by 5 publications

References 18 publications

Ignition energy scaling of inertial confinement fusion targets

Ignition energy scaling of inertial confinement fusion targets

Low initial aspect-ratio direct-drive target designs for shock- or self-ignition in the context of the laser Megajoule

Issues for magnetic and inertial fusion energy development

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