Accurate Stellar Opacities To Solve Astrophysical Problems

为了在大范围内对自然进行任何详细的研究，我们通常需要对支配我们宇宙的微观过程有一个精确的了解。其中之一称为不透明度，它测量电磁辐射(光，以各种形式)与原子、分子和自由漂浮的亚原子粒子相互作用的精确方式。最近对太阳内部的研究结果表明，以前对元素相对丰度的计算偏离了令人不快的数量。PI和他的合作者是实验室天体物理学领域的世界领先者。它们将提高由恒星内部计算机模型的结果指导的不透明度计算的准确性，通过最近的实验物理结果，并通过包括以前忽略的影响。虽然它主要是理论上的，但这项工作在天体物理学内外有着非常广泛的实际应用。其中包括核聚变和医学物理学。该协会积极参与多个项目，促进美印在STEM教育领域的合作努力。这个项目将包括对这一多学科研究的博士后研究员进行专门培训。PI将领导一项工作，利用改进的原子数据和新的高精度版本的不透明度项目代码，正确地解释无束缚自电离共振，并计算各种成分的平均不透明度。最近的日震学结果，桑迪亚国家实验室Z-Pinch惯性聚变装置的结果，以及对当前不透明度的重新检查，都表明真正的不透明度明显高于目前的模型。这项工作可能会导致“太阳丰度问题”的解决，它几乎肯定会导致基本原子物理的改善，包括适用于恒星内部的状态方程，包括在r-过程核合成中产生的元素的不透明度，以及改进的Rosseland和Planck平均不透明度。这是PI和他的合作者在最近的测量和计算技术改进的指导下，先前成功工作的延续和延伸。结果将通过电子数据库提供给物理、化学和天体物理学团体。

In order to carry out any detailed study of nature on large scales, we often require a precise understanding of the microscopic processes that govern our universe. One of these, called opacity, measures the precise way that electromagnetic radiation (light, in all of its forms) interacts with atoms, molecules, and free-floating subatomic particles. Recent results from studies of the Sun's interior indicate that previous calculations of the relative abundance of the elements are off by an uncomfortable amount. The PI and his collaborators are world leaders in the field of laboratory astrophysics. They will improve the accuracy of opacity calculations guided by results from computer models of stellar interiors, by recent experimental physics results, and by including effects that were previously omitted. While it is primarily theoretical, this work has a very broad range of practical applications in and beyond astrophysics. These include nuclear fusion and medical physics. The PI is active in several programs promoting collaborative US-India efforts in STEM education. This project will involve specialized training of a postdoctoral fellow in this multi-disciplinary research.The PI will lead an effort to properly account for bound-free autoionization resonances and calculate mean opacities for a variety of compositions using improved atomic data and a new high-precision version of the Opacity Project codes. Recent helioseismology results, results from the Z-pinch inertial fusion device at Sandia National Laboratory, and re-examination of current opacities all suggest that true opacities are significantly higher than current models. This work could lead to the solution of the "solar abundance problem", and it is all but guaranteed to lead to improvements in fundamental atomic physics, the equation of state appropriate for stellar interiors that incorporates opacities of elements produced in r-process nucleosynthesis, and improved Rosseland and Planck mean opacities. It is a continuation and extension of prior successful work by the PI and his collaborators, guided by recent measurements and by improvements in computational techniques. Results will be made available to the physics, chemistry, and astrophysics communities via electronic databases.