论文标题
时间分辨的XUV不透明度测量温度的铝
Time-resolved XUV Opacity Measurements of Warm-Dense Aluminium
论文作者
论文摘要
等离子体中的自由不透明度是我们对恒星内部能量运输和惯性限制融合研究的理解至关重要的。但是，在具有挑战性的密集等离子体制度中的理论预测是矛盾的，并且缺乏准确的实验数据以允许直接模型验证。在这里，我们提出了通过XUV自由电子激光加热的固体密度AL的时间分辨传输测量。我们使用一种新型的功能优化方法直接从过采样的单发测量池中提取温度依赖性吸收系数，并在将血浆加热到费米能量的温度时，找到不透明度的明显增强。在飞秒Xuv脉冲的持续时间内，在超快的时间尺度上观察到血浆加热和不透明度增强。我们将PS时标的不透明度进一步归因于融化和暖密度物质的形成。
The free-free opacity in plasmas is fundamental to our understanding of energy transport in stellar interiors and for inertial confinement fusion research. However, theoretical predictions in the challenging dense plasma regime are conflicting and there is a dearth of accurate experimental data to allow for direct model validation. Here we present time-resolved transmission measurements in solid-density Al heated by an XUV free-electron laser. We use a novel functional optimization approach to extract the temperature-dependent absorption coefficient directly from an oversampled pool of single-shot measurements, and find a pronounced enhancement of the opacity as the plasma is heated to temperatures of order the Fermi energy. Plasma heating and opacity-enhancement is observed on ultrafast time scales, within the duration of the femtosecond XUV pulse. We attribute further rises in the opacity on ps timescales to melt and the formation of warm-dense matter.
