磁约束聚变方案中的磁镜、场反及偶极场位形研究进展

Advances in Magnetic Mirror,Field Reversed Configuration,and Dipole Field in Magnetic Confinement Fusion

随着高温超导技术的日趋成熟,中小型磁约束装置的优势日渐明显。与大型托卡马克相比,偶极场、场反位形和磁镜等装置的结构相对简单,建造和维护成本较低,且更易实现能维持高等离子体压强的磁场位形,这意味着在低磁场下能实现更好的等离子体约束。此外,这些装置在物理原理上具有各自独特的优势,如磁镜装置具有开放的磁场位形和相对简单的结构设计,能支持灵活多样的实验并保持相对稳态运行;场反位形(FRC)装置的极高β值(β为等离子体压强与磁压之比)使得基于FRC的聚变装置在工程上更可行;偶极场装置因其类似地球磁场位形,具有天然良好的磁流体稳定性,有助于维持等离子体的约束。本文重点介绍了磁约束聚变方案中的磁镜、场反位形及偶极场的研究历史、技术进展和未来发展方向,阐述了这3类装置在聚变能研究中的重要性及面临的挑战。此类装置的小型化和经济性也使其在商业化方面更具潜力,能更灵活地进行技术调整和技术创新融合,吸引更多商业资本投入,加速聚变能的实现。

With the advancing of high-temperature superconducting technology,the advantages of small-sized and medium-sized magnetic confinement devices are becoming increasingly evident.Compared to traditional tokamaks,magnetic confinement devices such as dipole fields configurations,field reversed configurations(FRCs),and magnetic mirrors possess several notable advantages.These devices all have simpler structures,which results in lower construction and maintenance costs.At the same time,these devices are easier to achieve high-beta configurations.This means they can achieve better plasma confinement at low magnetic fields.In addition,these devices have their unique physical advantages.Magnetic mirror devices possess an open magnetic field configuration and a relatively simple structural design.They enable flexible and diverse experiments and can maintain steady-state operation.And the tandem mirrors improve the confinement and solve the problem of low fusion power gain.FRC is being explored as a potential fusion pathway due to its extremely highβvalue and engineering simplicity.And FRC also has a simple magnetic field configuration and geometric structure,making the construction of fusion devices based on FRCs more feasible from an engineering perspective.When discussing dipole fields,in addition to having relatively simple magnetic field structure and highβvalue,the dipole field device also benefits from its magnetic field configuration being like the Earth’s magnetic field,which inherently provides good MHD stability and helps to maintain plasma confinement.This article provides a comprehensive review of the research history,technological advancements,and future development directions of magnetic mirrors,FRCs,and dipole field devices within magnetic confinement fusion schemes.The review includes a detailed exploration of the evolution of these technologies,tracing their origins from early conceptual designs to their current state of development.Furthermore,this article addresses the specific challenges each device faces.For magnetic mirrors,it discusses issues related to cross-sectional loss,confinement efficiency and stability.For FRCs,the issues include poor confinement and a lack of effective current drive,leading to a generally low lifetime for most FRCs.For dipole fields,it explores the complexities associated with achieving and sustaining the desired magnetic field configurations.Despite these challenges,the compact size and cost-effectiveness of magnetic mirrors,FRCs,and dipole field devices make them highly promising from a commercial standpoint.The paper concludes by discussing the potential for these devices to play a significant role in the future of fusion energy.