预加热效果对磁化套筒惯性聚变放能影响的模拟研究

Simulation of the Preheating Effects on the Discharging of Magnetized Liner Inertial Fusion

得益于预加热和轴向磁场的作用,理论上磁化套筒惯性聚变(MagLIF)构型能有效降低聚变实现的难度,具有极大的应用潜力。然而,当前研究过于重视对激光能量沉积效率的提升,而忽略了预加热自身参数对MagLIF过程和内爆结果的影响。为此,采用一维集成化数值模拟程序MIST,开展了MagLIF过程中预加热效果对聚变放能影响的模拟研究,基于参数扫描方法,从简单的模型着手,逐步深入探讨相关参数对内爆结果的影响。模拟结果表明:预加热是MagLIF构型能够成功的必要条件,最佳时间是套筒即将开始向内压缩燃料的时刻;燃料预加热的设计原则是让燃料获得尽可能平缓分布的高温,而中心局部加热方式对于未能达到点火条件的负载更有优势;激光预加热模式下,脉宽越短越好,对于以ZR装置驱动能力为目标的算例而言,最佳套筒高度为1.0 cm。研究结果有助于加深对MagLIF过程中预加热机制和效果的认知和理解,对于具体的负载参数设计也有较强的指导意义。

Benefiting from laser preheating and axial magnetization,magnetized liner inertial fusion(MagLIF)has great application potential because it can effectively reduce the difficulties to realize the controlled fusion in theory.However,much attention has been paid to the improvement of laser energy deposition efficiency in current research,while the influence of preheating parameters on the MagLIF process and implosion is ignored.For this reason,the one-dimensional integrated simulation code,MIST,is used here to study the preheating effect on the fusion discharging in MagLIF process.Based on the method of parameter scanning,starting from a simple model,the studies of the influences of relevant parameters on implosion results are gradually advanced.The simulation results show that preheating is a necessary condition for the success of MagLIF configuration,and the best preheating time is the moment when the liner is about to compress the fuel.The design principle of preheating is to allow the fuel to acquire as smoothly distributed high temperature as possible,and the central local heating mode is more advantageous when the ignition fails.If the laser is preheated,the shorter pulse width will be better.For driving ability of ZR facility,the optimal liner height is 1.0 cm.These results are not only helpful to understand laser preheating mechanism and effect during MagLIF process,but also providing useful guidance for the design of the detail load parameters of MagLIF configuration.