基于温度梯度的ICF冷冻靶均化技术研究

惯性约束聚变(ICF)冷冻靶中氘氘(D2)、氘氚(DT)等燃料冰层在靶丸中的分布由靶丸所处的温度场决定。在氘氘冷冻靶中,垂直温度梯度引起的气-液界面张力梯度可以抵消重力作用,使氘氘液体在靶丸内均匀分布;然后在氘氘的三相点附近缓慢降温,可以实现燃料冰层的均化。在氘氘冷冻靶均化实验系统上,采用温度梯度结合制冷速率与制冷过程控制的方法,实现了1mm直径、30μm壁厚的辉光放电聚合物(GDP)靶丸中氘氘冰层的均化,对背光阴影图像中亮环位置进行分析表明:氘氘冰层的平均厚度为185.56μm,均匀度为80.2%,模数-功率谱曲线中模数2~100对应的内表面粗糙度为2.26μm。

Fuel layering of ICF cryogenic target based on temperature gradient method

The spatial distribution of deuterium (D2) or deuterium-tritium (DT) ice condensed inside the inertial confinement fusion (ICF) spherical cryogenic target is determined by the temperature field around the target. In the deuterium cryogenic target, the uniform liquid is formed by the vapor-liquid interfacial tension gradient resulting from the vertical temperature gradient, which counterbalances the gravity-induced fuel sagging. The uniform D2 solid layer can be achieved by slow cooling toward the triple point of D2. The layering process of D2 ice in a glow discharge polymer (GDP) shell of 1mm diameter and 30m thickness is demonstrated experimentally by imposing vertical temperature gradient combined with control of cooling rate. Calculated from the bright ring in backlit shadowgraphy, the average thickness and uniformity of D2 ice layer are 185.56 m and 80.2% respectively, the inner surface roughness of the ice from mode 2 to 100 in power spectrum is about 2.26 m.