冲击波产生温稠密氘氦混合物状态诊断及物性研究

Strong shock waves have the special advantage of producing lots of novel phenomena which are otherwise difficult to be observed,which promotes the development and flourish of condensed matter theories and plasma theories applied in warm dense matter regime. The warm dense matter, as a transient or final matter state,is essentially important for the research of inertial confinement fusion ,heavy-ion inerial fusion,Z-pinch processes and so on,in particular, its thermodynamic properties and radiation transfer characteristics are vitally important for the design of fusion experiments and the simulation of the dynamic processes. Currently, the development of the shock wave technology makes it possible and feasible to manipulate the ionization and dissociation processes in atoms and molecules.Therefore,this proposal chooses a deuterium and helium mixture, representing the mixture of an important fusion reactant and fusion product,as the research target, aiming:(1) to investigate the production, confinement,equation-of-state diagnostics,and temporally resolved optical emission characteristics, (2) to evaluate the effect of the D2/He mixture ratio on the the balance of ionization and dissociation reactions and the associated mixing rules under a strong shock wave,(3) to establish a thermodynamic model and equation-of-state calculation method including the effects of pressure/temperature induced ionization and dissociation in atoms and molecules under the constraint of local thermo-equilibrium approximation,in the hope of solving the difficult,but urgently needed problems of determining the equation of state,the mechanical-thermal-optical-electrical-acoustic properties and the mechanisms of ionization and dissociation processes in atoms and molecules under extreme conditions,providing a reliable basis for the development of condensed matter theories (and plasma theories) applied in warm dense matter regime.

冲击波会引发许多其它手段难以观察到的新奇物理现象，对于丰富和发展温稠密条件下凝聚态与等离子体理论具有特殊优势。温稠密物质是惯性约束聚变、重离子聚变、Z箍缩动作过程中物质发展和存在的重要阶段，其热力学性质和辐射输运参数在聚变实验设计和动力学模拟中起至关重要作用。冲击波技术的发展使温稠密物质中原子分子的电离和离解变得可操控，因此，本项目拟选择聚变反应物氘与生成物氦的混合物作为研究对象，开展 (1) 冲击波作用下温稠密物质产生、约束、状态诊断及时间分辨光谱研究；(2)冲击波作用下，不同氦氘混合比例对离解和电离效应的影响及混合规则研究；(3) 建立高温高压局域热动平衡条件下，考虑压力和温度导致原子分子电离和离解的热动力学模型和物态方程计算方法。 解决当下迫切需要且存在困难的温稠密区混合物质物态方程、物性、原子分子电离和离解等实际作用机制问题，为研究温稠密条件下凝聚态理论提供科学依据。

本项目选择聚变反应物氘与生成物氦的混合物作为研究对象，利用二级轻气炮作为加载手段产生冲击波，从初始预压缩氘氦等摩尔混合气体状态出发经冲击波多次反射压缩产生温稠密物质，并应用多种联合诊断手段，获取了从兆帕到兆巴压力(MPa ~Mbar)、温度几千开到万开的宽压力温度范围氘氦混合物物态方程以及兆巴压力区准等熵声速数据。在基于实验验证基础上，构建了高温高压局域热动平衡条件下，考虑了压力和温度导致原子分子电离和离解的自洽流体变分热力学模型，数值模拟研究了氘氦混合比例对离解和电离效应的影响，模拟结果显示高温高压氘氦稠密物质主要由D2,D, D+,e, He, He+粒子构成。利用所建立模型和数值方法进一步对氘氦混合物在等温、绝热、等熵压缩过程混合比例X对物性调控机制进行研究，数值模拟发现混合组分x不仅对其压缩热力学状态可以进行调控，而且也可以调控混合物中的氘的离解度，尤其是可以调控单次绝热压缩最大压缩比，这些模拟结果可以为深度认识混合物P(压力)-V(比容)-T(温度)-X(组分)调控机理提供依据。DT混合气体聚变反应物与生成物主要是由氘、氚、氦等元素组成，氢、氦等元素也是气态巨行星内部主要组成物质，温稠密物质是DT聚变和巨行星内部必然要经历的中间物质状态，设计聚变实验和构建行星内部结构模型等都需要氘氚氦混合物在非常宽广的温度密度区域的状态方程、辐射和输运参数。因此，本项目获得氘氦混合物实验数据和建立模型，对于聚变设计和行星物理问题解决等都具有重要科学意义和应用背景。