考虑材料强度的金属丝电爆炸相变特征研究

The wire-array Z-Pinch has been regarded as one of the most competitive approaches to realize the Inertial Confinement Fusion with the advantages of strong X-ray radiation power and very high transfer efficiency from electromagnetic energy to radiant energy. The stage of electrical explosion of metal wires has critical impact on the stability, quality of imploding and X-ray yield of wire-array Z-Pinch. However, the key theoretical problem of phase transition of the metal wire driven by the pulsed current in the first phase of wire-array Z-Pinch is not fully understood, which limits the investigation on seed mechanism for instability, and greatly restrict the further developments of wire-array Z-Pinch. In this project, the material strength model, describing the elastic-plastic deformation of metallic load, will be coupled to the computational model with “cold-start” conditions of electrical explosion of metal wires. The equation of state is combined with material strength model to describe the response of metal wire to the pulsed current self-consistently. The researches will be focused on the “cold-start” numerical simulation and experimental investigation on phase transition of metal wire from solid to plasma state. Through the studies in this project, the influence of material strength on the phase transition will be illuminated. The research provides a deep insight into the physical process of phase transition and the characteristics of phase transition driven by the pulsed current are to be revealed. These prospective achievements could provide theoretical basis for the investigation on the seed mechanism of the wire-array Z-Pinch.

丝阵Z箍缩具有超强的X射线辐射功率和很高的电磁能-辐射能转换效率，被认为是一种很有竞争力的惯性约束聚变能源的实现途径。金属丝电爆炸阶段对丝阵Z箍缩的稳定性、内爆质量和X射线产额具有重要的影响。然而，人们对脉冲电流驱动金属丝相变这一关键理论问题的认识尚不清晰，限制了对内爆不稳定性种子机制的研究，极大地制约了丝阵Z箍缩的进一步发展。本项目拟在建立的金属丝电爆炸“冷启动”物理数学模型的基础上，耦合能够描述负载弹-塑性形变的材料强度模型，以物态方程结合材料强度模型自洽地描述金属丝对脉冲电流的响应，围绕金属丝从固态到等离子体态的相变开展“冷启动”数值模拟和实验研究。通过本项目的研究，可阐明材料强度对相变过程的影响机理，深入认识金属丝电爆炸相变的物理过程，揭示脉冲电流驱动金属丝相变的特征，为丝阵Z箍缩不稳定性种子机制研究奠定理论基础。

丝阵Z箍缩具有超强的X射线辐射功率和很高的电磁能-辐射能转换效率，被认为是一种很有竞争力的惯性约束聚变能源的实现途径，在核爆X射线模拟、武器物理和天体物理等领域也有重要的应用价值。金属丝电爆炸阶段对丝阵Z箍缩的稳定性、内爆质量和X射线产额具有关键的影响。然而，人们对脉冲电流驱动金属丝相变这一关键理论问题的认识尚不清晰，限制了对内爆不稳定性种子机制的研究，极大地制约了丝阵Z箍缩的进一步发展。本项目在前期研究中建立的金属丝电爆炸“冷启动”物理数学模型的基础上，耦合了能够描述负载弹-塑性形变的材料强度模型，以物态方程结合材料强度模型自洽地描述金属丝对脉冲电流的响应。基于脉冲电流驱动金属丝相变的背景氛围环境，在磁流体力学方程组中加入了能够描述负载等离子体与背景氛围气体相互作用的对流方程，建立了多流体种类、双温金属丝电爆炸“冷启动”物理数学模型。围绕金属丝电爆炸相变开展了“冷启动”数值模拟和实验研究，通过平行双丝电爆炸实验的自发光波形验证了负载等离子体与背景氛围气体相互作用对等离子体融合过程的重要影响，阐明了负载材料强度对相变过程的影响机理，结合金属丝负载从金属态到非金属态的转变，深入认识金属丝从固态、液态、气态到等离子体态相变的物理过程，揭示了脉冲电流驱动金属丝相变的特征。本项目的研究可以更加深入地理解丝阵Z箍缩的物理过程，为推进丝阵Z箍缩不稳定性种子机制的研究奠定了理论基础。