We present the first simulation results of a multi-shell target ignition driven by Z-pinch dynamic hohlraum radiation pulse.The radiation pulse is produced with a special Z-pinch dynamic hohlraum configuration,where t...We present the first simulation results of a multi-shell target ignition driven by Z-pinch dynamic hohlraum radiation pulse.The radiation pulse is produced with a special Z-pinch dynamic hohlraum configuration,where the hohlraum is composed of a single metal liner,a low-Z plastic foam,and a high-Z metallic foam.The implosion dynamics of a hohlraum and a multi-shell target are investigated separately by the one-dimensional code MULTI-IFE.When the peak drive current is 50 MA,simulations suggest that an x-ray pulse with nearly constant radiation temperature(-310 eV)and a duration about 9 ns can be obtained.A small multi-shell target with a radius of 1.35 mm driven by this radiation pulse is able to achieve volumetric ignition with an energy gain(G)about 6.19,where G is the ratio of the yield to the absorbed radiation.Through this research,we better understand the effects of non-uniformities and hydrodynamics instabilities in Z-pinch dynamic hohlraum.展开更多
Radiation uniformity is important for Z-pinch dynamic hohlraum driven fusion. In order to understand the radiation uniformity of Z-pinchdynamic hohlraum, the code MULTI-2D with a new developed magnetic field package i...Radiation uniformity is important for Z-pinch dynamic hohlraum driven fusion. In order to understand the radiation uniformity of Z-pinchdynamic hohlraum, the code MULTI-2D with a new developed magnetic field package is employed to investigate the related physical processeson Julong-I facility with drive current about 7e8 MA. Numerical simulations suggest that Z-pinch dynamic hohlraum with radiation temperaturemore than 100 eV can be created on Julong-I facility. Although some X-rays can escape out of the hohlraum from Z-pinch plasma and electrodes, the radiation field near the foam center is quite uniform after a transition time. For the load parameters used in this paper, the transitiontime for the thermal wave transports from r = 1 mm to r = 0 mm is about 2.0 ns. Implosion of a testing pellet driven by cylindrical dynamichohlraum shows that symmetrical implosion is hard to achieve due to the relatively slow propagation speed of thermal wave and the compressionof cylindrical shock in the foam. With the help of quasi-spherical implosion, the hohlraum radiation uniformity and corresponding pelletimplosion symmetry can be significantly improved thanks to the shape modulation of thermal wave front and shock wave front.展开更多
Three-dimensional(3D)hydrodynamic numerical simulations of laser driven thin-shell gas-filled microballoons have been carried out using the computer code MULTI-3D[Ramis et al.,Phys.Plasmas 21,082710(2014)].The studied...Three-dimensional(3D)hydrodynamic numerical simulations of laser driven thin-shell gas-filled microballoons have been carried out using the computer code MULTI-3D[Ramis et al.,Phys.Plasmas 21,082710(2014)].The studied configuration corresponds to experiments carried at the ORION laser facility[Hopps et al.,Plasma Phys.Controlled Fusion 57,064002(2015)].The MULTI-3D code solves single-temperature hydrodynamics,electron heat transport,and 3D ray tracing with inverse bremsstrahlung absorption on unstructured Lagrangian grids.Special emphasis has been placed on the genuine 3D effects that are inaccessible to calculations using simplified 1D or 2D geometries.These include the consequences of(i)a finite number of laser beams(10 in the experimental campaign),(ii)intensity irregularities in the beam crosssectional profiles,(iii)laser beam misalignments,and(iv)power imbalance between beams.The consequences of these imperfections have been quantified by post-processing the numerical results in terms of capsule nonuniformities(synthetic emission and absorption images)and implosion efficiency(convergence ratio and neutron yield).Statistical analysis of these outcomes allows determination of the laser tolerances that guarantee a given level of target performance.展开更多
The use of the Laser MegaJoule facility within the shock ignition scheme has been considered. In the first part of the study, one-dimensional hydrodynamic calculations were performed for an inertial confinement fusion...The use of the Laser MegaJoule facility within the shock ignition scheme has been considered. In the first part of the study, one-dimensional hydrodynamic calculations were performed for an inertial confinement fusion capsule in the context of the shock ignition scheme providing the energy gain and an estimation of the increase of the peak power due to the reduction of the photon penetration expected during the high-intensity spike pulse. In the second part, we considered a Laser MegaJoule configuration consisting of 176 laser beams that have been grouped providing two different irradiation schemes. In this configuration the maximum available energy and power are 1.3 MJ and 440 TW. Optimization of the laser–capsule parameters that minimize the irradiation non-uniformity during the first few ns of the foot pulse has been performed. The calculations take into account the specific elliptical laser intensity profile provided at the Laser MegaJoule and the expected beam uncertainties. A significant improvement of the illumination uniformity provided by the polar direct drive technique has been demonstrated. Three-dimensional hydrodynamic calculations have been performed in order to analyse the magnitude of the azimuthal component of the irradiation that is neglected in twodimensional hydrodynamic simulations.展开更多
A numerical method providing the optimal laser intensity profiles for a direct-drive inertial confinement fusion scheme has been developed. The method provides an alternative approach to phase-space optimization studi...A numerical method providing the optimal laser intensity profiles for a direct-drive inertial confinement fusion scheme has been developed. The method provides an alternative approach to phase-space optimization studies, which can prove computationally expensive. The method applies to a generic irradiation configuration characterized by an arbitrary number NBof laser beams provided that they irradiate the whole target surface, and thus goes beyond previous analyses limited to symmetric configurations. The calculated laser intensity profiles optimize the illumination of a spherical target.This paper focuses on description of the method, which uses two steps: first, the target irradiation is calculated for initial trial laser intensities, and then in a second step the optimal laser intensities are obtained by correcting the trial intensities using the calculated illumination. A limited number of example applications to direct drive on the Laser Mega Joule(LMJ) are described.展开更多
基金Project supported by the Science Challenge Project (Grant No. TZ2018001)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos. XDA25051200 and XDA25050200)+4 种基金the National Natural Science Foundation of China (Grant Nos. 11705282 and 11775305)Hunan Graduate Scientific Research Innovation Project (Grant No. CX20190001)supported by the spanish “Ministerio de Ciencia Innovación y Universidades”project RTI2018-098801-B-100the Spanish “Ministerio de Economía y Competitividad” Project ENE2014-54960-Rthe EURO fusion Consortium project AWP15-ENR-01/CEA-02
文摘We present the first simulation results of a multi-shell target ignition driven by Z-pinch dynamic hohlraum radiation pulse.The radiation pulse is produced with a special Z-pinch dynamic hohlraum configuration,where the hohlraum is composed of a single metal liner,a low-Z plastic foam,and a high-Z metallic foam.The implosion dynamics of a hohlraum and a multi-shell target are investigated separately by the one-dimensional code MULTI-IFE.When the peak drive current is 50 MA,simulations suggest that an x-ray pulse with nearly constant radiation temperature(-310 eV)and a duration about 9 ns can be obtained.A small multi-shell target with a radius of 1.35 mm driven by this radiation pulse is able to achieve volumetric ignition with an energy gain(G)about 6.19,where G is the ratio of the yield to the absorbed radiation.Through this research,we better understand the effects of non-uniformities and hydrodynamics instabilities in Z-pinch dynamic hohlraum.
基金This work was supported by the National Natural Science Foundation of China(Nos.11374357,11475153,11705282,and 11475260)Science Challenge Project(No.TZ2018001)+2 种基金Research Project of NUDT(Grant No.ZK16-03-29)the Spanish Ministerio de Economia y Competivida project(No.ENE2014-54960-R)the EUROfusion Consortium project AWP15-ENR-01/CEA-02.
文摘Radiation uniformity is important for Z-pinch dynamic hohlraum driven fusion. In order to understand the radiation uniformity of Z-pinchdynamic hohlraum, the code MULTI-2D with a new developed magnetic field package is employed to investigate the related physical processeson Julong-I facility with drive current about 7e8 MA. Numerical simulations suggest that Z-pinch dynamic hohlraum with radiation temperaturemore than 100 eV can be created on Julong-I facility. Although some X-rays can escape out of the hohlraum from Z-pinch plasma and electrodes, the radiation field near the foam center is quite uniform after a transition time. For the load parameters used in this paper, the transitiontime for the thermal wave transports from r = 1 mm to r = 0 mm is about 2.0 ns. Implosion of a testing pellet driven by cylindrical dynamichohlraum shows that symmetrical implosion is hard to achieve due to the relatively slow propagation speed of thermal wave and the compressionof cylindrical shock in the foam. With the help of quasi-spherical implosion, the hohlraum radiation uniformity and corresponding pelletimplosion symmetry can be significantly improved thanks to the shape modulation of thermal wave front and shock wave front.
基金The research of R.R.was supported by the Spanish Ministerio de Econom´ıa y Competitividad,Project No.ENE2014-54960-R and by the EUROfusion Consortium under Project No.AWP15-ENR-01/CEA-02.M.T.is supported by CEA-ENS LRC-MESO Grant No.2018-011.
文摘Three-dimensional(3D)hydrodynamic numerical simulations of laser driven thin-shell gas-filled microballoons have been carried out using the computer code MULTI-3D[Ramis et al.,Phys.Plasmas 21,082710(2014)].The studied configuration corresponds to experiments carried at the ORION laser facility[Hopps et al.,Plasma Phys.Controlled Fusion 57,064002(2015)].The MULTI-3D code solves single-temperature hydrodynamics,electron heat transport,and 3D ray tracing with inverse bremsstrahlung absorption on unstructured Lagrangian grids.Special emphasis has been placed on the genuine 3D effects that are inaccessible to calculations using simplified 1D or 2D geometries.These include the consequences of(i)a finite number of laser beams(10 in the experimental campaign),(ii)intensity irregularities in the beam crosssectional profiles,(iii)laser beam misalignments,and(iv)power imbalance between beams.The consequences of these imperfections have been quantified by post-processing the numerical results in terms of capsule nonuniformities(synthetic emission and absorption images)and implosion efficiency(convergence ratio and neutron yield).Statistical analysis of these outcomes allows determination of the laser tolerances that guarantee a given level of target performance.
基金the support given to this work. R. R. was partially supported by the EURATOM/CIEMAT association in the framework of the ‘IFE Keep-in-Touch Activities’. S. W.acknowledges support from the Czech Science Foundation (Project No. CZ.1.07/2.3.00/20.0279) and from ELI (Project No. CZ.1.05/1.1.00/02.0061)
文摘The use of the Laser MegaJoule facility within the shock ignition scheme has been considered. In the first part of the study, one-dimensional hydrodynamic calculations were performed for an inertial confinement fusion capsule in the context of the shock ignition scheme providing the energy gain and an estimation of the increase of the peak power due to the reduction of the photon penetration expected during the high-intensity spike pulse. In the second part, we considered a Laser MegaJoule configuration consisting of 176 laser beams that have been grouped providing two different irradiation schemes. In this configuration the maximum available energy and power are 1.3 MJ and 440 TW. Optimization of the laser–capsule parameters that minimize the irradiation non-uniformity during the first few ns of the foot pulse has been performed. The calculations take into account the specific elliptical laser intensity profile provided at the Laser MegaJoule and the expected beam uncertainties. A significant improvement of the illumination uniformity provided by the polar direct drive technique has been demonstrated. Three-dimensional hydrodynamic calculations have been performed in order to analyse the magnitude of the azimuthal component of the irradiation that is neglected in twodimensional hydrodynamic simulations.
基金partially supported by the EURATOM/CIEMAT association in the framework of the ‘IFE Keep-in-Touch Activities’
文摘A numerical method providing the optimal laser intensity profiles for a direct-drive inertial confinement fusion scheme has been developed. The method provides an alternative approach to phase-space optimization studies, which can prove computationally expensive. The method applies to a generic irradiation configuration characterized by an arbitrary number NBof laser beams provided that they irradiate the whole target surface, and thus goes beyond previous analyses limited to symmetric configurations. The calculated laser intensity profiles optimize the illumination of a spherical target.This paper focuses on description of the method, which uses two steps: first, the target irradiation is calculated for initial trial laser intensities, and then in a second step the optimal laser intensities are obtained by correcting the trial intensities using the calculated illumination. A limited number of example applications to direct drive on the Laser Mega Joule(LMJ) are described.
