背光阴影成像表征降温速率对ICF冷冻冰层均化的影响

摘要

利用背光阴影成像技术研究了降温速率对惯性约束聚变（ICF）球形氘氘冷冻靶中燃料冰层均化的影响．实验中，首先对ICF冷冻靶温度场进行标定以确定靶丸处的温度，然后利用背光阴影成像系统对降温过程中靶丸内燃料冰层的空间变化进行实时原位测量，得到了不同降温条件下冷冻靶背光阴影成像图像中亮环的功率谱．实验结果表明：相比快速降温，台阶式缓慢降温有利于形成均匀的燃料冰层；同时验证了背光阴影成像技术表征ICF冷冻靶内冷冻冰层均化的有效性．%The effect of cooling rate on layering the deuterium ice inside inertial confinement fusion (ICF)spherical cryotarget is studied by backlit shadowgraphy. Experimentally, the temperature of ice is first determined by the calibration of temperature field around ICF cryotarget. The solidification process of deuterium in the cryotarget is in- situ characterized by backlit shadowgraphy. The power- spectrum density of the bright ring in shadowgraphy at different cooling rates is obtained. Experimental results demonstrate that the step-gradient slow cooling is favorable for forming uniform fuel ice in comparison with the rapid cooling. Furthermore, the validity of characterizing the ICF cryotarget layering by the backlit shadowgraphy is also verified.