Understanding fuel magnetization and mix using secondary nuclear reactions in magneto-inertial fusion.
Understanding fuel magnetization and mix using secondary nuclear reactions in magneto-inertial fusion.
复制标题
使用磁惯性聚变中的二次核反应了解燃料磁化和混合。
DOI：
10.1103/physrevlett.113.155004
复制
发表时间：
2014
影响因子：
8.6
通讯作者：
R. Vesey
中科院分区：
文献类型：
--
作者：
P. Schmit;P. Knapp;S. B. Hansen;M. Gomez;K. Hahn;D. Sinars;K. Peterson;S. Slutz;A. Sefkow;T. Awe;E. Harding;C. A. Jennings;G. Chandler;G. Cooper;M. Cuneo;M. Geissel;A. Harvey;M. Herrmann;M. H. Hess;O. Johns;D. Lamppa;M. R. Martin;R. D. McBride;J. L. Porter;G. Robertson;G. Rochau;D. Rovang;C. L. Ruiz;M. E. Savage;I. C. Smith;W. Stygar;R. Vesey
在惯性约束聚变中，磁化燃料通过降低导热性和改变燃烧产物约束的物理性质来放松点火要求。诊断燃料在燃烧过程中的磁化程度对于理解磁惯性聚变（MIF）内爆中的目标性能至关重要。在纯氘聚变等离子体中，1.01 MeV的氚子在氘-氘聚变期间发射，并且在离开燃料之前可以经历二次氘-氚反应。增加燃料磁化会延长一些triton通过燃料的路径长度，提高它们反应的概率。基于这一特点，发展了一种利用氘氚总中子产额与氘氘中子产额之比诊断燃料磁化的方法。对次级中子能谱各向异性的分析进一步限制了测量。二次反应也被证明提供了一个上限的体积燃料推进混合在MIF。本文的分析应用于最近的MIF实验[M. R. Gomez等人，物理修订信函113，155003（2014）]，表明实现了带电燃烧产物的显著磁约束，并表明相对低混合的环境。这两者都是未来点火级MIF设计的基本特征。
Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing the physics of burn product confinement. Diagnosing the level of fuel magnetization during burn is critical to understanding target performance in magneto-inertial fusion (MIF) implosions. In pure deuterium fusion plasma, 1.01 MeV tritons are emitted during deuterium-deuterium fusion and can undergo secondary deuterium-tritium reactions before exiting the fuel. Increasing the fuel magnetization elongates the path lengths through the fuel of some of the tritons, enhancing their probability of reaction. Based on this feature, a method to diagnose fuel magnetization using the ratio of overall deuterium-tritium to deuterium-deuterium neutron yields is developed. Analysis of anisotropies in the secondary neutron energy spectra further constrain the measurement. Secondary reactions also are shown to provide an upper bound for the volumetric fuel-pusher mix in MIF. The analysis is applied to recent MIF experiments [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z Pulsed Power Facility, indicating that significant magnetic confinement of charged burn products was achieved and suggesting a relatively low-mix environment. Both of these are essential features of future ignition-scale MIF designs.