Application of view-factor method in calculations of radiation transport in targets

Bazin, A.; Vatulin, V.; Dementyev, Yu. A.; Mironova, V.F.; Skidan, G.I.; Tikhomirova, B.N.; Tikhomirov, B.P.

doi:10.1016/s0168-9002(98)00505-1

Cited by 12 publications

(3 citation statements)

References 6 publications

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“…Where PL is the power of all of lasers, a η is scattering rate of lasers, x η is conversion efficiency of laser to x-ray, α is the albedo, A W is total area of irradiated surfaces in the spherical hohlraum, and A LEH is total area of laser entrance holes. From equation (1), we can compute average radiation flux S , r and then estimate the incident flux S in for any element on the capsule through a practical view-factor model [9][10][11][12][13].…”

Section: Radiation Flux and Driven Symmetry Computation On The Fuel T...mentioning

confidence: 99%

A novel scheme for direct drive target with enhanced radiation

Jiang¹,

Huang²,

Jing³

et al. 2015

Phys. Scr.

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A novel directly driven target with enhanced radiation is presented in this paper. A spherical hohlraum with laser entrance holes is built to allow lasers to be injected onto the directly driven capsule without intersection. The additional spherical hohlraum can be utilized to absorb a portion of scattering lasers, and generate x-ray to re-radiate the centrally located capsule, in which the laser efficiency and driven symmetry on the capsule are demonstrated to be significantly improved.

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Section: Radiation Flux and Driven Symmetry Computation On The Fuel T...mentioning

confidence: 99%

A novel scheme for direct drive target with enhanced radiation

Jiang¹,

Huang²,

Jing³

et al. 2015

Phys. Scr.

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“…In the ICF, the radiation flux on the fuel capsule is related to the laser-plasma interactions (LPI) and transport of X-rays from the cavity wall to the capsule, which involves the solving of complex kinetic and hydrodynamic equations implemented in the codes such as LASNEX [3]. In practice, simple mathematical models such as view-factor codes are usually employed to compute the radiation flux distributed on the capsule, especially for the preliminary design and optimization of thermonuclear target structure and shape [3], [4]. As described in [1], the radiation flux is usually obtained by solving a non-linear view-factor based equation model, which can be solved by utilizing Newton-Rapshon [5], Jacobi iteration [6], Cholesky decomposition [7], or Preconditioned Conjugate Gradient method [8].…”

Section: Introductionmentioning

confidence: 99%

Sparse Representation Based Efficient Radiation Symmetry Analysis Method for Cylindrical Model of Inertial Confinement Fusion

Zhang

2019

Preprint

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Radiation symmetry evaluation is critical to the laser driven Inertial Confinement Fusion (ICF), which is usually done by solving a view-factor equation model. The model is nonlinear, and the number of equations can be very large when the size of discrete mesh element is very small to achieve a prescribed accuracy, which may lead to an intensive equation solving process. In this paper, an efficient radiation symmetry analysis approach based on sparse representation is presented, in which, 1) the Spherical harmonics, annular Zernike polynomials and Legendre-Fourier polynomials are employed to sparsely represent the radiation flux on the capsule and cylindrical cavity, and the nonlinear energy equilibrium equations are transformed into the equations with sparse coefficients, which means there are many redundant equations, 2) only a few equations are selected to recover such sparse coefficients with Latin hypercube sampling, 3) a Conjugate Gradient Subspace Thresholding Pursuit (CGSTP) algorithm is then given to rapidly obtain such sparse coefficients equation with as few iterations as possible. Finally, the proposed method is validated with two experiment targets for Shenguang II and Shenguang III laser facility in China. The results show that only one tenth of computation time is required to solve one tenth of equations to achieve the radiation flux with comparable accuracy. Further more, the solution is much more efficient as the size of discrete mesh element decreases, in which, only 1.2% computation time is required to obtain the accurate result.

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“…This yields some difficulties in the practical ICF experimental design, and in practice, simple mathematical models such as view-factor codes are usually applied to estimate the radiation flux on the capsule, especially for the preliminary design and optimization of thermonuclear target structure and shape. 27,28 Therefore, view-factor-based models are applied in this study to evaluate the drive symmetry and temperature of the capsule.…”

Section: Introductionmentioning

confidence: 99%

Novel free-form hohlraum shape design and optimization for laser-driven inertial confinement fusion

et al. 2014

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The hohlraum shape attracts considerable attention because there is no successful ignition method for laser-driven inertial confinement fusion at the National Ignition Facility. The available hohlraums are typically designed with simple conic curves, including ellipses, parabolas, arcs, or Lame curves, which allow only a few design parameters for the shape optimization, making it difficult to improve the performance, e.g., the energy coupling efficiency or radiation drive symmetry. A novel free-form hohlraum design and optimization approach based on the non-uniform rational basis spline (NURBS) model is proposed. In the present study, (1) all kinds of hohlraum shapes can be uniformly represented using NURBS, which is greatly beneficial for obtaining the optimal available hohlraum shapes, and (2) such free-form uniform representation enables us to obtain an optimal shape over a large design domain for the hohlraum with a more uniform radiation and higher drive temperature of the fuel capsule. Finally, a hohlraum is optimized and evaluated with respect to the drive temperature and symmetry at the Shenguang III laser facility in China. The drive temperature and symmetry results indicate that such a free-form representation is advantageous over available hohlraum shapes because it can substantially expand the shape design domain so as to obtain an optimal hohlraum with high performance.

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Application of view-factor method in calculations of radiation transport in targets

Cited by 12 publications

References 6 publications

A novel scheme for direct drive target with enhanced radiation

A novel scheme for direct drive target with enhanced radiation

Sparse Representation Based Efficient Radiation Symmetry Analysis Method for Cylindrical Model of Inertial Confinement Fusion

Novel free-form hohlraum shape design and optimization for laser-driven inertial confinement fusion

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