高电荷态离子在等离子体中的双电子复合过程研究

The charge exchange between Highly Charged Ions (HCIs) with plasma is not only the most popular process happening in fusion plasma and astrophysical plasma, but also is the focus for the plasma stripper development in heavy ion accelerator. Due to the large amount of free electrons in plasma, the dielectric combination (DR) process between the HCIs with free electron probably play the dominant role for the charge exchange. However, The precise mechanism is still not clarified, and the current theory and data library is in highly demand to be benchmarked. In this project, based on the for ion-plasma interaction research platform at HIRFL, we will build a novel experimental method for DR research on one hand, and on the other hand, obtain the DR resonance condition information and rate coefficient. The DR interaction environment in plasma is constructed through finely adjusting the projectile velocity. The analysis is based on the measurement of the X ray emission during the beam-plasma interaction as well as the charge state distribution passing through the plasma. In addition, the measurement for a series of plasma density will also be done to clarify the charge state evolution and the equilibration process of HCIs in plasma. in the related field, our team has solid foundation in both experimental research and theoretical calculation, and is expected to realize the DR process study directly in plasma environment for the first time and get good achievement at the end.

高电荷态离子与等离子体作用中的电荷交换过程是聚变物理和天体物理领域涉及的关键微观作用过程，同时也是强流重离子加速器新型等离子体剥离技术的核心研究内容。由于等离子体中存在大量的自由电子,高电荷态离子与自由电子的双电子复合过程将会扮演重要的角色，相关物理建模和参数可靠性亟待实验检验。本项目将基于HIRFL上的离子束与等离子体相互作用实验平台，建立等离子体环境中双电子复合过程研究的实验新方法，1）首次通过精细调节离子束能量，观测出射离子电荷态分布及X射线强度两个重要特征信息，研究高电荷态离子在等离子体中的双电子复合共振条件及其反应速率；2）通过改变等离子体密度，精确调节离子在等离子体中的作用长度，观测和研究共振区域附近离子束在等离子体中的电荷态演化及其平衡过程。项目组成员及其研究团队前期实验和理论研究基础良好，经验丰富，有望率先实现等离子体环境中的DR实验观测并取得具有较高创新性的研究成果。

高电荷态离子与等离子体作用中的电荷交换过程是聚变物理和天体物理领域涉及的关键微观作用过程，同时也是强流重离子加速器新型等离子体剥离技术的物理基础。在该项目的支持下，课题组依托兰州重离子加速器HIRFL装置，测量了高电荷态离子与物质相互作用中发射的X射线，结果表明离子-原子碰撞中4fσ-4fπ准分子轨道跃迁通道有个能量阈值，高于该阈值后，该电荷交换通道将会打开，从而引起靶原子电离截面的显著增加；测量了百keV量级离子束穿过气体放电等离子体中的能量和电荷态分布，实验验证了包含碰撞电离、辐射复合、双电子复合等重要过程的理论模型；课题组还利用激光聚变研究中心星光III强激光装置测量了激光加速碳离子束穿过稠密等离子体后的电荷态分布，发现离子束电荷态分布明显改变，相关数据和物理机制仍在分析中。上述研究结果对于理解高电荷态离子与等离子体作用的微观机制、检验热核聚变及天体等离子体相关物理模型和参数可靠性具有重要意义。