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2018 Vol. 3, No. 3

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High Pressure Physics and Materials Science
Review Articles
Recent advance in high-pressure solid-state metathesis reactions
Lei Li, Zhang Leilei
2018, 3(3) doi: 10.1016/j.mre.2017.12.003
Abstract:
High-pressure solid-state metathesis (HPSSM) reaction is an effective route to novel metal nitrides. A recent advance in HPSSM reactions is presented for a number of examples, including 3d transition metal nitrides (ε-Fe3N, ε-Fe3−xCoxN, CrN, and Co4Nx), 4d transition metal nitrides (MoNx), and 5d transition metal nitrides (Re3N, WNx). Thermodynamic investigations based on density functional theory (DFT) calculations on several typical HPSSM reactions between metal oxides and boron nitride indicate that the pressure could reduce the reaction enthalpy ΔH. High-pressure confining environment thermodynamically favors an ion-exchange process between metal atom and boron atom, and successfully results in the formation of well-crystalized metal nitrides with potential applications.
Laser- and Particle Beam Fusion
Research Articles
Macroscopic laser–plasma interaction under strong non-local transport conditions for coupled matter and radiation
Nikl J., Holec M., Zeman M., Kuchařík M., Limpouch J., Weber S.
2018, 3(3) doi: 10.1016/j.mre.2018.03.001
Abstract:
Reliable simulations of laser–target interaction on the macroscopic scale are burdened by the fact that the energy transport is very often non-local. This means that the mean-free-path of the transported species is larger than the local gradient scale lengths and transport can be no longer considered diffusive. Kinetic simulations are not a feasible option due to tremendous computational demands, limited validity of the collisional operators and inaccurate treatment of thermal radiation. This is the point where hydrodynamic codes with non-local radiation and electron heat transport based on first principles emerge. The simulation code PETE (Plasma Euler and Transport Equations) combines both of them with a laser absorption method based on the Helmholtz equation and a radiation diffusion scheme presented in this article. In the case of modelling ablation processes it can be observed that both, thermal and radiative, transport processes are strongly non-local for laser intensities of 1013W/cm2 and above. In this paper simulations for various laser intensities and different ablator materials are presented, where the non-local and diffusive treatments of radiation transport are compared. Significant discrepancies are observed, supporting importance of non-local transport for inertial confinement fusion related studies as well as for pre-pulse generated plasma in ultra-high intensity laser–target interaction.
Recent progress in ICF target fabrication at RCLF
Du Kai, Liu Meifang, Wang Tao, He Xiaoshan, Wang Zongwei, Zhang Juan
2018, 3(3) doi: 10.1016/j.mre.2017.12.005
Abstract:
Target is one of the essential parts in inertial confinement fusion (ICF) experiments. To ensure the symmetry and hydrodynamic stability in the implosion, there are stringent specifications for the target. Driven by the need to fabricate the target required by ICF experiments, a series of target fabrication techniques, including capsule fabrication techniques and the techniques of target characterization and assembly, are developed by the Research Center of Laser Fusion (RCLF), China Academy of Engineering Physics (CAEP). The capsule fabrication techniques for preparing polymer shells, glow discharge polymer (GDP) shells and hollow glass micro-sphere (HGM) are studied, and the techniques of target characterization and assembly are also investigated in this paper. Fundamental research about the target fabrication is also done to improve the quality of the target. Based on the development of target fabrication techniques, some kinds of target have been prepared and applied in the ICF experiments.
Self-modulation and anomalous collective scattering of laser produced intense ion beam in plasmas
Mima K., Fuchs J., Taguchi T., Alvarez J., Marquès J.R., Chen S.N., Tajima T., Perlado J.M.
2018, 3(3) doi: 10.1016/j.mre.2017.12.004
Abstract:
The collective interaction between intense ion beams and plasmas is studied by simulations and experiments, where an intense proton beam produced by a short pulse laser is injected into a pre-ionized gas. It is found that, depending on its current density, collective effects can significantly alter the propagated ion beam and the stopping power. The quantitative agreement that is found between theories and experiments constitutes the first validation of the collective interaction theory. The effects in the interaction between intense ion beams and background gas plasmas are of importance for the design of laser fusion reactors as well as for beam physics.
A novel superconducting magnetic levitation method to support the laser fusion capsule by using permanent magnets
Li Xiaojia, Xiao Tingting, Chen Fengwei, Zhang Yingjuan, Li Xiaofei, Wu Weidong
2018, 3(3) doi: 10.1016/j.mre.2018.01.004
Abstract:
A novel magnetic levitation support method is proposed, which can relieve the perturbation caused by traditional support methods and provide more accurate position control of the capsule. This method can keep the perfect symmetry of the octahedral spherical hohlraum and has the characteristics in stability, tunability and simplicity. It is also favorable that all the results, such as supporting forces acting on the superconducting capsule, are calculated analytically, and numerical simulations are performed to verify these results. A typical realistic design is proposed and discussed in detail. The superconducting coating material is suggested, and the required superconducting properties are listed. Damped oscillation of the floating capsule in thin helium gas is discussed, and the restoring time is estimated.