Bulletin of the American Physical Society最新文献_第9页

Hydro-scaling of direct-drive cylindrical implosions at the OMEGA and the National Ignition Facility 欧米茄和国家点火装置直接驱动圆柱内爆的水力结垢

Bulletin of the American Physical Society Pub Date : 2019-10-24 DOI: 10.1063/1.5144608

S. Palaniyappan, J. Sauppe, B. Tobias, C. F. Kawaguchi, K. Flippo, A. Zylstra, O. Landen, D. Shvarts, E. Malka, S. Batha, P. Bradley, E. Loomis, N. Vazirani, L. Kot, D. Schmidt, T. H. Day, R. Gonzales, J. Kline

{"title":"Hydro-scaling of direct-drive cylindrical implosions at the OMEGA and the National Ignition Facility","authors":"S. Palaniyappan, J. Sauppe, B. Tobias, C. F. Kawaguchi, K. Flippo, A. Zylstra, O. Landen, D. Shvarts, E. Malka, S. Batha, P. Bradley, E. Loomis, N. Vazirani, L. Kot, D. Schmidt, T. H. Day, R. Gonzales, J. Kline","doi":"10.1063/1.5144608","DOIUrl":"https://doi.org/10.1063/1.5144608","url":null,"abstract":"Deceleration-phase Rayleigh–Taylor instability (RTI) growth during inertial confinement fusion capsule implosions significantly affects the performance as it mixes cold ablator material into the fuel. Precise measurements of such instability growth are essential for both validating the existing simulation codes and improving our predictive capability. RTI measurements on the inner surface of a spherical shell are limited and are often inferred indirectly at limited convergence. In contrast, cylindrical implosions allow for direct diagnostic access to the converging interface by imaging down the cylinder axis while retaining the effects of convergence. We have performed direct-drive cylindrical implosion experiments at both the OMEGA and the NIF laser facilities using scaled targets. RTI growth is demonstrated to be scale-invariant between the cylindrical targets at OMEGA and similar targets at the NIF, which are scaled up by a factor of three in the radial dimension. Single-mode (m = 20) instability growth factors of ∼14 are measured at a convergence ratio (CR) ∼ 2.5 with nearly identical mode growth at both scales. The measurements are in agreement with xRAGE radiation-hydrodynamics simulations. In addition, we have developed the Bayesian-inference-engine method to account for the variations in the target alignment, magnification, and the parallax effect in the measurement, allowing a more precise comparison between the experimental data and the simulations.","PeriodicalId":9375,"journal":{"name":"Bulletin of the American Physical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78364101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 16

Advances in physics understanding of high poloidal beta regime toward steady-state operation of CFETR 对CFETR稳态运行的高极向β状态的物理认识进展

Bulletin of the American Physical Society Pub Date : 2019-10-23 DOI: 10.1063/5.0032490

J. Qian, A. Garofalo, X. Gong, J. Huang, S. Ding, C. Holcomb, A. Hyatt, J. Ferron, J. Mcclenaghan, G. McKee, M. Kotschenreuther, M. Q. Wu, S. Shi, M. Li, X. Zhu, Y. Sun, G. Xu, L. Wang, J. Chen, Q. Zang, B. Zhang, L. Zhang, H. Liu, B. Lyu, W. Guo, C. Pan, Q. Ren, G. Li, H. Wang, X. Zhang, R. Pinsker, G. Staebler, L. Lao

{"title":"Advances in physics understanding of high poloidal beta regime toward steady-state operation of CFETR","authors":"J. Qian, A. Garofalo, X. Gong, J. Huang, S. Ding, C. Holcomb, A. Hyatt, J. Ferron, J. Mcclenaghan, G. McKee, M. Kotschenreuther, M. Q. Wu, S. Shi, M. Li, X. Zhu, Y. Sun, G. Xu, L. Wang, J. Chen, Q. Zang, B. Zhang, L. Zhang, H. Liu, B. Lyu, W. Guo, C. Pan, Q. Ren, G. Li, H. Wang, X. Zhang, R. Pinsker, G. Staebler, L. Lao","doi":"10.1063/5.0032490","DOIUrl":"https://doi.org/10.1063/5.0032490","url":null,"abstract":"Experimental and modeling investigations of high βp scenarios on DIII-D and EAST tokamaks show advantages in high energy confinement, avoidance of n = 1 MHD, and core-edge integration with reduced heat flux, making this scenario an attractive option for China Fusion Engineering Test Reactor steady-state operation. Experiments show that plasmas with high confinement and high density can be achieved with neutral beam injection on DIII-D (βp ∼ 2.2, βN ∼ 3.5, fBS ∼ 50%, fGw ∼ 1.0, and H98y2 ∼ 1.5) and pure RF power on EAST (βP ∼ 2.0, βN ∼ 1.6, fBS ∼ 50%, fGw ∼ 0.8, and H98y2 > 1.3). By tailoring the current density profile, a q-profile with local (off-axis) negative shear is achieved, which yields improved confinement and MHD stability. Transport analysis and simulation suggest that the combination of a high density gradient and high Shafranov shift allows turbulence stabilization and higher confinement. Using on-axis Electron Cyclotron Heating injection, tungsten accumulation is avoided on EAST, and this is reproduced in modeling. Reduced heat flux (by > 40%) and maintenance of high core confinement is achieved with active feedback control of the radiated divertor, an important result for long pulse operation in tokamaks. The improved physics understanding and validated modeling tools are used to design a 1 GW steady-state scenario for CFETR.","PeriodicalId":9375,"journal":{"name":"Bulletin of the American Physical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88971696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Complex-Hamiltonian paraxial description of damped geodesic acoustic modes 阻尼测地线声模的复哈密顿傍轴描述

Bulletin of the American Physical Society Pub Date : 2019-10-23 DOI: 10.1063/5.0009636

E. Poli, F. Palermo, A. Bottino, O. Maj, H. Weber

{"title":"Complex-Hamiltonian paraxial description of damped geodesic acoustic modes","authors":"E. Poli, F. Palermo, A. Bottino, O. Maj, H. Weber","doi":"10.1063/5.0009636","DOIUrl":"https://doi.org/10.1063/5.0009636","url":null,"abstract":"Geodesic acoustic modes (GAMs) are a fundamental part of turbulence and zonal-flow dynamics in tokamaks. They exhibit simple yet non-trivial dispersive and dissipative properties. In linear numerical simulations, they are often initialized in the form of (e.g., Gaussian) packets that evolve in time. Depending on the parameters, dispersion and damping can act on comparable time scales during the GAM evolution. Wigner-function methods developed in the frame of non-Hermitian quantum mechanics are shown to be applicable to damped geodesic oscillations. In this approach, the standard approximation of “weak damping,” often introduced for the treatment of plasma waves, is not needed. The method requires that the properties of the plasma do not vary significantly across the width of the packet (i.e., in the radial direction), so that a paraxial expansion of the underlying equations around the center of the packet can be applied. For a quadratic Hamiltonian, the equations for the Wigner function governing the packet in the paraxial limit are shown to be equivalent to the equations of paraxial WKB theory (usually applied to the description of high-frequency wave beams in plasmas), with the real Hamiltonian replaced by the corresponding complex one. Analytic solutions are derived in particular cases and shown to agree with the results of global gyrokinetic simulations.","PeriodicalId":9375,"journal":{"name":"Bulletin of the American Physical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87094884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

First implementation of gyrokinetic exact linearized Landau collision operator and comparison with models 首次实现了陀螺动力学精确线性化朗道碰撞算子，并与模型进行了比较

Bulletin of the American Physical Society Pub Date : 2019-10-22 DOI: 10.1063/1.5143374

Q. Pan

{"title":"First implementation of gyrokinetic exact linearized Landau collision operator and comparison with models","authors":"Q. Pan","doi":"10.1063/1.5143374","DOIUrl":"https://doi.org/10.1063/1.5143374","url":null,"abstract":"Gyrokinetic simulations are fundamental to understanding and predicting turbulent transport in magnetically confined fusion plasmas. Previous simulations have used model collision operators with approximate field-particle terms of unknown accuracy and/or have neglected collisional finite Larmor radius (FLR) effects. We have implemented the linearized Fokker–Planck collision operator with exact field-particle terms and full FLR effects in a gyrokinetic code (GENE). The new operator, referred to as “exact” in this paper, allows the accuracy of model collision operators to be assessed. The conservative Landau form is implemented because its symmetry underlies the conservation laws and the H-theorem, and enables numerical methods to preserve this conservation, independent of resolution. The implementation utilizes the finite-volume method recently employed to discretize the Sugama collision model in GENE, allowing direct comparison between the two operators. Results show that the Sugama model appears accurate for the growth rates of trapped electron modes (TEMs) driven only by density gradients, but appreciably underestimates the growth rates as the collisionality and electron temperature gradient increase. The TEM turbulent fluxes near the nonlinear threshold using the exact operator are similar to the Sugama model for the η e = d ln T e / d ln n e = 0 case, but substantially larger than the Sugama model for the η e = 1 case. The FLR effects reduce the growth rates increasingly with wavenumber, deepening a “valley” at the intermediate binormal wavenumber as the unstable mode extends from the TEM regime to the electron temperature gradient instability regime. Application to the Hinton–Rosenbluth problem shows that zonal flows decay faster as the radial wavenumber increases and the exact operator yields weaker decay rates.","PeriodicalId":9375,"journal":{"name":"Bulletin of the American Physical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82572283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

Modeling the 3-D structure of ignition experiments at the NIF 模拟NIF点火实验的三维结构

Bulletin of the American Physical Society Pub Date : 2019-10-21 DOI: 10.1063/1.5142509

R. Nora, J. Field, B. Spears, D. Casey, M. Kruse, D. Mariscal, P. Patel

引用次数: 4

A simple hydride model for cerium ejecta particles 铈喷射粒子的简单氢化物模型

Bulletin of the American Physical Society Pub Date : 2019-09-26 DOI: 10.2172/1569587

J. Regele

引用次数: 0

Ex Luna, Scientia: The Lunar Occultation eXplorer (LOX) 前月球，科学:月球掩星探测器(LOX)

Bulletin of the American Physical Society Pub Date : 2019-07-16 DOI: 10.2172/1544647

Richard S. Miller, M. Ajello, J. Beacom, P. Bloser, A. Burrows, C. Fryer, J. Goldsten, D. Hartmann, P. Hoeflich, A. Hungerford, D. Lawrence, M. Leising, P. Milne, P. Peplowski, Farzane Shirazi, T. Sukhbold, L. The, Z. Yokley, C. A. Young

{"title":"Ex Luna, Scientia: The Lunar Occultation eXplorer (LOX)","authors":"Richard S. Miller, M. Ajello, J. Beacom, P. Bloser, A. Burrows, C. Fryer, J. Goldsten, D. Hartmann, P. Hoeflich, A. Hungerford, D. Lawrence, M. Leising, P. Milne, P. Peplowski, Farzane Shirazi, T. Sukhbold, L. The, Z. Yokley, C. A. Young","doi":"10.2172/1544647","DOIUrl":"https://doi.org/10.2172/1544647","url":null,"abstract":"LOX is a lunar-orbiting astrophysics mission that will probe the cosmos at MeV energies. It is guided by open questions regarding thermonuclear, or Type-Ia, supernovae (SNeIa) and will characterize these inherently radioactive objects by enabling a systematic survey of SNeIa at gamma-ray energies for the first time. Astronomical investigations from lunar orbit afford new opportunities to advance our understanding of the cosmos. The foundation of LOX is an observational approach well suited to the all-sky monitoring demands of supernova investigations and time-domain astronomy. Its inherently wide field-of-view and continuous all-sky monitoring provides an innovative way of addressing decadal survey questions at MeV energies (0.1-10 MeV). The LOX approach achieves high sensitivity with a simple, high-heritage instrument design that eliminates the need for complex, position-sensitive detectors, kinematic event reconstruction, masks, or other insensitive detector mass, while also mitigating technology development, implementation complexity, and their associated costs. LOX can be realized within existing programs, like Explorer.","PeriodicalId":9375,"journal":{"name":"Bulletin of the American Physical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74562932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A reactive molecular dynamics study of phenol and phenolic polymers in extreme environments 极端环境下苯酚和酚醛聚合物的反应分子动力学研究

Bulletin of the American Physical Society Pub Date : 2019-06-21 DOI: 10.1063/12.0001031

Keith Jones, J. Lane, N. W. Moore

引用次数: 2

Single crystal plasticity model with deformation twinning for the high rate deformation of β-HMX 高速率变形β-HMX的变形孪晶单晶塑性模型

Bulletin of the American Physical Society Pub Date : 2019-06-21 DOI: 10.1063/12.0001018

Milovan Zecevic, D. Luscher, M. Cawkwell, F. Addessio, K. Ramos

引用次数: 3

Overdriven-detonation states produced by spherically diverging waves 由球形发散波产生的超驱动爆轰状态

Bulletin of the American Physical Society Pub Date : 2019-06-20 DOI: 10.1063/12.0000923

Matthew M. Biss, M. Lieber, Michael R. Martinez

引用次数: 1