摘要
在“神光Ⅱ”装置上进行了激光直接驱动爆推型和烧蚀型DT气体的玻璃微球靶内爆实验 .采用多道滤波 荧光谱仪 (FFS)测量 1 5— 2 5 0keV硬x射线谱 ,由高能x射线谱通量和斜率推算出这两种内爆靶产生的超热电子份额ηhe和超热电子温度Th 分别为 ηhe=2 5 %— 30 % ,Th=30— 4 0keV和 ηhe=0 5 %— 4 % ,Th=10— 2 0keV .并给出了不同内爆靶型在不同激光能量EL 和不同调焦方式下超热电子产生的特征 ,由爆推靶产生超热电子份额与实验测量靶的能量吸收效率 ηa=2 9%— 34%比对 ,证明爆推靶吸收的激光能量是以超热电子能量沉积为主 ,同时实验观测中子产额Yn 随超热电子能量Ehe的增大而增大 。
The implosion experiments of laser directly driven filled DT glass capsules were performed on the “ShenguangⅡ' facility by ways of exploding pushing and ablating. Hard x ray spectra in the energy range of 1 5—250keV were measured using the multi channel filter fluorescenuce spectrometer (FFS). The fractions and temperatures of hot electrons for exploding pusher targets are η he =25%—30% and T h=30—40keV, respectively, and those for ablation targets are η he =0 5%—4% and T h=10—25keV, respectively, which were inferred from the fluxes and slopes of high energy x rays. The characteristic of producing hot electrons for various types of targets was given under different incident laser energy E L and spot adjustment. It has been proved by comparing hot electron fractions of exploding pusher targets with the measured energy absorption efficiency η a, which is between 29% and 34%, that energy deposition of hot electrons is the major energy absorption mechanism for exploding pusher targets. The experimental results show that neutron yield increases with hot electron energy E he , which shows that the implosion of exploding pusher target happens mainly by hot electrons heating the glass ball shell.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2002年第9期2068-2073,共6页
Acta Physica Sinica
基金
国家高技术研究发展计划 (批准号 :863 416 3 )资助的课题~~
