稠密氦气辐射不透明度的实验研究

用二级氢气炮作为冲击压缩加载工具和多通道瞬态辐射高温计作为主要测量系统,测量了冲击压缩氦气等离子体的光辐亮度历史(初始温度293 K,初始压力为0.6 MPa和1.2 MPa两种).根据实测记录信号波形的有关特征量,计算得到了氦等离子体的光谱吸收系数κ(λ)和冲击压缩铝基板表面的光反射率R.结果发现:受冲击铝基板表面的光反射率～0.4(比其初始反射率0.8约降低一半),与Erskine的数据相同;对于光谱吸收系数的实测数据,本文目前未能给出合理的物理解释.

Studies on opacity of dense helium at high temperatures

The initial pressure is 0.6 MPa and 1.2 MPa and the initial temperature is 293 K. The pressure and the temperature region of the shock-compressed state are from 50～180 MPa and from 6 000 K～14 000 K, respectively. The results demonstrated: the spectrum absorption coefficients, corresponding to the optic measuring channels, are also obtained, which are of important to the radiation transport property of the helium plasma at low temperatures, But, we ware not yet found the relevant physical model to ionterpret them, the measured reflectivity of aluminum (baseplate) surface after shocked is about 0.4, a half-decrease of its normal value of ～0.8. This after-shocked value of reflectivity will influence on the confidence of calculated spectrum absorption coefficient, and its value is then of important significance. Though the data of ～0.4 was reported by Erskine before, the way of its determination had not been given.