温稠密物质中不同价态离子分布对X-射线弹性散射光谱计算的影响

在天体物理和惯性约束聚变研究中涉及到的温稠密物质通常包含多种元素的混合,并且每种元素还被电离成多种离子价态,不同价态离子结构及其丰度将直接影响温稠密物质的诊断及其物理性质.同时,从电子结构计算出发来研究宏观物理性质时,还需要考虑温度、密度效应对离子结构的影响.本文从不同价态离子的电子结构计算出发,采用考虑了离子间相互作用的Saha方程获得了稠密环境下的离子丰度,并使用超网链(hypernetted-chain)近似对铝、金以及碳-氢混合物的径向分布函数进行了计算,结合离子周围电子的密度分布,最后获得X-射线汤姆逊散射的弹性散射谱.在X-射线散射谱计算中,计算了温稠密物质中同时存在不同离子价态时的电子结构和径向分布函数,发现在相同的等离子体环境下不同价态离子的径向分布函数和电子结构差别较大.这将对依赖于微观统计过程的物理性质,比如散射光谱,将产生较大的影响.

Influence of different charge-state ion distribution on elastic X-ray scattering in warm dense matter

The study of warm dense matter is very important for the evolution of celestial bodies and inertial confinement fusion,which often contains a mixture of multiple elements and different charge-state ions.The ionic structure and distribution of different charge-states directly affect the diagnosis and physical properties of warm dense matter.At the same time,the influence of high-temperature dense plasma on the ionic structure should be considered when we study the physical properties from the first-principle calculation of electron structure.In the present work,the radial distribution functions of multiple charge-state ions(gold,carbonhydrogen mixture,and aluminum)are developed in the hypernetted-chain approximation,and elastic x-ray scattering of different charge-state ions are calculated in the warm dense matter regime.Firstly,the electron structure of different charge-state ions is self-consistently computed in the ionic sphere,in which the ion-sphere radii are determined by the plasma density and their charges.And then the ionic fraction is obtained by solving the modified Saha equation,with the interactions among different charge-state ions taken into account,and ionion pair potentials are obtained by Yukawa model.Finally,the ion features of x-ray elastic scattering for Al are calculated on the basis of electronic distribution around the nuclei and ionic radial distribution function.By comparing the results of different charge-sate ions with the result of mean charge-sate ion,it is shown that different statistical methods can affect the physical properties which are dependent on the electronic and ionic structure.