摘要
在100 kJ激光装置上开展了基于三台阶整形脉冲的间接驱动惯性约束聚变内爆实验研究.采用传统充气直柱金壁黑腔设计,在激光脉冲作用后期,腔内金等离子体运动对激光能量沉积和X光辐射场空间分布产生严重扰动,导致靶丸赤道驱动偏弱,形成不可接受的扁圆内爆.本文采用新型的花生腔设计,通过调节外环激光光斑及其产生的金泡的初始位置,补偿和缓解金等离子体运动对黑腔X光辐射分布产生的扰动影响,获得球对称的靶丸辐射驱动.在靶丸驱动辐射温度相同的条件下,由于驱动对称性得到显著改善,实验观测到花生腔内爆热斑接近球形,中子产额的测量结果与内爆一维模拟计算结果的比值(YOS)达到30%;而直柱腔内爆热斑呈现扁圆形状,YOS仅为13%.模拟计算和实验结果一致表明,在三台阶整形脉冲驱动内爆实验中,花生腔设计可以有效抑制外环金泡膨胀加剧产生的不利因素,增强辐射驱动和内爆对称性调控,并提高内爆性能.
Indirect-driven inertial confinement fusion implosions using a three-step-shaped pulse are performed at a 100 kJ laser facility. At late time of the pulse, deposition of laser energy and distribution of X-ray radiation are significantly disturbed by motion of gold plasma in the original gas-filled cylindrical hohlraum with gold wall.As a result, owing to the lack of X-ray drive at the equator of the capsule, an unacceptable oblate implosion is produced. In the I-raum modified from the above cylindrical hohlraum, the initial positions of outer laser spots and gold bubbles are appropriately shifted to modify the disturbed radiation distribution due to plasma evolution, resulting in a spherically symmetric drive on the capsule. In the implosion shots with almost the same drive pulse, owing to improved symmetry, an spherical hotspot is observed in the new I-raum, and YOS(the ratio of measured neutron yield over simulated one) is up to 30%, while an oblate hotspot is observed in the cylinder, and YOS is only 13%. The simulation calculations and experimental measurements show that the I-raum can be used to significantly reduce the impact of gold bubble expansion in the three-step-shaped pulse driven implosion, which helps to tune the drive and implosion symmetry, and to improve its over-all performance.
作者
黄天晅
吴畅书
陈忠靖
晏骥
李欣
葛峰峻
张兴
蒋炜
邓博
侯立飞
蒲昱东
董云松
王立锋
Huang Tian-Xuan;Wu Chang-Shu;Chen Zhong-Jing;Yan Ji;Li Xin;Ge Feng-Jun;Zhang Xing;Jiang Wei;Deng Bo;Hou Li-Fei;Pu Yu-Dong;Dong Yun-Song;Wang Li-Feng(Research Center of Laser Fusion,Mianyang 621900,China;Institute of Applied Physics and Computational Mathematics,Beijing 100088,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第2期190-199,共10页
Acta Physica Sinica
基金
国家自然科学基金(批准号:12075221,12075220)资助的课题.
关键词
惯性约束聚变
间接驱动
内爆对称性
inertial confinement fusion
indirect-drive
implosion symmetry