在质子照相中利用Abel逆变换反演等离子体自生磁场结构  

Self-generated magnetic field in plasma reconstructed by using inverse Abel transformation in proton radiography

作　　者：邓娈 杜报 蔡洪波[3,4] 康洞国[3] 朱少平 Deng Luan;Du Bao;Cai Hong-Bo;Kang Dong-Guo;Zhu Shao-Ping(School of Nuclear Science and Technology,University of Science and Technology of China,Hefei 230026,China;Graduate School,China Academy of Engineering Physics,Beijing 100088,China;Institute of Applied Physics and Computational Mathematics,Beijing 100094,China;Center for Applied Physics and Technology,Peking University,Beijing 100871,China)

机构地区：[1]中国科学技术大学核科学技术学院,合肥230026 [2]中国工程物理研究院研究生院,北京100088 [3]北京应用物理与计算数学研究所,北京100094 [4]北京大学应用物理与技术研究中心,北京100871

出　　处：《物理学报》2022年第24期312-318,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11975055);国家自然科学基金青年科学基金(批准号:12105023)资助的课题。

摘　　要：质子照相是观测等离子体中自生磁场的常用实验诊断技术,对质子照相实验结果的有效解读依赖于反演方法的可靠性和可用性.传统质子照相反演方法往往只能提供自生磁场的一维或二维结构.本研究发现,在对具有柱对称结构的磁场进行侧向质子照相时,偏转速度与磁场之间满足Abel变换关系,这使得从质子照相结果中反演重建出磁场的三维结构成为可能.通过数值模拟验证了该方法的可行性,并基于该反演方法,重新分析了Li等(2016 Nat.Commun.713081)有关等离子体喷流自生磁场的质子照相实验结果,给出的最大磁场强度约为传统反演结果的1.9倍.本研究有助于对激光聚变和实验室天体物理相关的自生电磁场形成及其时空演化行为的认识更加清晰.The magnetic fields generated in plasmas have extensive influences on many processes of the inertial confinement fusion and the astrophysics.Therefore,the quantitative diagnosis of the magnetic field is quite essential.Proton radiography is a widely used experimental technique to diagnose the electric field or magnetic field in high-energy-density plasma.The effective explanation of the results of proton radiography depends on the reliability and availability of the inversion method.Traditional inversion methods can only provide one-or two-dimensional structure of the self-generated magnetic field.In this study,it is found that there is an Abel transformation relationship between the deflection velocity and the magnetic field with column symmetry,which allows us to reconstruct the three-dimensional structure of the magnetic field for the first time.We theoretically deduce the process of reconstructing the cylindrical magnetic field through proton radiography with the Abel inversion algorithm.The feasibility of this method is verified by numerical simulation as well.Based on this inversion method,we reanalyze the proton radiography experimental results of Li et al.(2016Nat.Commun.713081)on the self-generated magnetic field of plasma jets.The inversion results show that the maximum magnetic field intensity is about 1.9 times the traditional inversion results.We discuss a new proton radiography inversion method for the existence of magnetic fields with cylindrical symmetry in thiswork,which will contributes to an intensive understanding of the self-generated electromagnetic field and its spatiotemporal evolution related to the laser fusion and the laboratory astrophysics.

关 键 词：质子照相 反演 磁场诊断 Abel逆变换 

分 类 号：O53[理学—等离子体物理]