物理学报2026，Vol.75Issue(1)：220-230,11.DOI:10.7498/aps.75.20251144
太阳辐射/对流区域边界处的碳、氮、氧元素的电子碰撞电离研究
Electron impact ionization of C,N,and O at boundary of solar radiation/convection zone
摘要
Abstract
The solar radiation-convection boundary(T～180 eV,ne～9× 1022 cm-3)marks the transition from radiative to convective energy transport,serving as a natural laboratory for hot dense plasmas.Its physical properties are crucial for stellar evolution and energy transport models,yet how electron-impact ionization(EII)is influenced by hot-dense environment effects—such as electron screening and ion correlation—remains unclear.To address this,we systematically calculate EII cross sections for C,N,and O ions under realistic solar boundary conditions,focusing on the role of environmental effects.We develop a novel computational framework that integrates hot-dense environment effects into atomic structure calculations:the Flexible Atomic Code(FAC)for atomic structure is combined with the Hypernetted-chain(HNC)approximation to capture electron-electron,electron-ion and ion-ion correlations,enabling self-consistent treatment of electron screening and ion correlation.Atomic wave functions are derived by solving the Dirac equation within the ion-sphere model,using a modified central potential that combines both free-electron screening and ion-ion interactions.EII cross sections are then computed via the distorted-wave(DW)approximation in FAC.The results demonstrate that the hot-dense environment effects significantly enhance the electron-impact ionization cross sections of C,N,and O,compared with those calculated under the free-atom model.Additionally,a notable reduction in the ionization threshold energy is observed.These effects are attributed to the overlap of atomic potentials due to strong ion coupling and the shift in bound-state energy levels caused by free-electron screening.For instance,under solar boundary conditions,the ionization cross section of C+is increased by up to 50％,with the ionization threshold decreasing from about 24 eV(isolated)to 18 eV(with screening).Similar enhancements are observed for nitrogen and oxygen ions across various charge states.By establishing updated ionization cross sections for C,N,and O ions under realistic solar interior conditions,this work provides fundamental parameters for improving radiation transport models,ionization balance calculations,and equation-of-state models in stellar interiors.The results underscore the necessity of incorporating hot-dense environment effects in the calculations of atomic processes in hot dense plasmas,which is of great significance for astrophysics and inertial confinement fusion research.关键词
辐射/对流区域边界/环境效应/电子碰撞电离/超网链近似Key words
radiation/convection zone boundary/environment effect/electron impact ionization/hypernetted-chain approximation引用本文复制引用
侯永,罗青波,梁欣,曾交龙,袁建民..太阳辐射/对流区域边界处的碳、氮、氧元素的电子碰撞电离研究[J].物理学报,2026,75(1):220-230,11.基金项目
科学挑战计划(批准号:TZ2025013)和国家自然科学基金(批准号:11974424)资助的课题. Project supported by the Science Challenge Project,China(Grant No.TZ2025013)and the National Natural Science Foundation of China(Grant No.11974424). （批准号:TZ2025013）
