磁化套筒惯性聚变一维集成化数值模拟

One-dimensional integrated simulations of magnetized liner inertial fusion

磁化套筒惯性聚变(magnetized liner inertial fusion,MagLIF)结合了传统磁约束聚变和惯性约束聚变的优点,理论上可以显著地降低聚变实现的难度,具有极大的应用潜力.以研究MagLIF中的关键问题为目标,建立能够综合考虑磁化、预加热、套筒内爆、聚变反应、端面效应、磁通压缩等多种复杂机制在内的集成化物理模型,特别是通过引入流体喷射模型,使得可以在一维计算条件下考虑具有二维特性的端面损失情况,并额外考虑Nernst扩散项对磁通损失的影响.在此基础上编写实现一维集成化MagLIF数值模拟程序MIST(magnetic implosion simulation tools),与FP-1装置(2 MA,7.2μs)上铝套筒内爆实验结果的对比验证了程序磁流体模块的正确性;将聚变模块纳入后与国外同类程序LASNEX和HYDRA计算结果进行整体比较,所得数值结果总体接近,主要差异体现在燃料温度的计算上,对可能影响的原因进行了简要分析.所建立的集成化模型与程序将为未来开展MagLIF聚变实验研究提供坚实的理论基础和重要工具.

Magnetized liner inertial fusion(MagLIF)integrates the advantages of traditional magnetic confinement fusion with those of inertial confinement fusion,and thus has promising potentials because theoretically it can dramatically lower the difficulties in realizing the controlled fusion.For the systematic simulating of MagLIF,we build up an integrated one-dimensional(1D)model to describe the complex process,which includes the terms of magnetization,laser preheating,liner implosion,fusion reaction,end loss effect,and magnetic flux compression.According to this model we develop an integrated 1D code–MIST(magnetic implosion simulation tools),and specifically we propose a simplified model to describe the end loss effect based on the flow bursting theory,so the code is able to consider two-dimensional effects within 1D calculations.We also present a specific expression of magnetic diffusion equation where the Nernst effect term is taken into consideration,which is very important if there exists a temperature gradient perpendicular to magnetic field lines.Such conditions are fully satisfied in the MagLIF process.We use experimental data of aluminum liner implosions to verify the magnetohydrodynamic module of our code,those shots(0607&0523)are performed on FP-1 facility(2 MA,7.2μs),and results show good agreement with the calculated velocity of inner flyer or target surface and other measurements.Comparison with code LASNEX and HYDRA(used by Sandia Laboratory)is also made to assess the fusion module,and the results show that our calculations are physically self-consistent and roughly coincide with the results from LASNEX and HYDRA,a key difference appears at fuel temperature,and the factors that might cause this difference are discussed.With this integrated model and 1D code,our work would provide a powerful tool for the future experimental research of MagLIF.