滤波反投影算法在太阳旋转层析成像中的应用
The Application of the Filtered Backprojection Algorithm to Solar Rotational Tomography
摘要：
太阳旋转层析成像（SRT）是重建三维日冕物理参数的重要方法。在这里，我们提出了一种方法，将滤波反投影（FBP）算法的SRT。由于太阳极紫外（EUV）观测存在的几个问题，特别是由于隐藏在太阳后面的日冕背面未被观测到而导致的数据缺失所造成的问题，FBP算法通常不适合SRT。我们开发了一种方法来生成一个修改的正弦图，解决了阻塞问题。修改后的正弦图是由太阳动力学天文台（SDO）上的大气成像组件（AIA）观测到的两个相对位置的EUV数据相结合而产生的。我们在2019年2月生成了大约一个月的修改后的正弦图，并在静态假设下重建了三维日冕。为了获得日冕的物理参数，我们采用了DEM反演方法。我们测试的FBP算法与修改后的正弦图的性能，通过比较重建的数据与观察到的EUV图像，电子密度模型，以前的研究电子温度，和观察到的coronagromatic图像。结果表明，FBP算法合理地重建了亮区和冕洞，并能再现它们的物理参数。FBP算法的主要优点是易于理解和计算效率高。因此，它使我们能够很容易地探测日冕的不均匀电子密度和温度分布。
英文摘要：
Solar rotational tomography (SRT) is an important method to reconstruct the physical parameters of the three-dimensional solar corona. Here we propose an approach to apply the filtered backprojection (FBP) algorithm to the SRT. The FBP algorithm is generally not suitable for SRT due to the several issues with solar extreme ultraviolet (EUV) observations, in particular a problem caused by missing data because of the unobserved back side of corona hidden behind the Sun. We developed a method to generate a modified sinogram which resolves the blocking problem. The modified sinogram is generated by combining the EUV data at two opposite sites observed by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). We generated the modified sinogram for about one month in 2019 February and reconstructed the three-dimensional corona under the static state assumption. In order to obtain the physical parameters of the corona, we employed a DEM inversion method. We tested the performance of the FBP algorithm with the modified sinogram by comparing the reconstructed data with the observed EUV image, electron density models, previous studies of electron temperature, and an observed coronagraph image. The results illustrate that the FBP algorithm reasonably reconstructs the bright regions and the coronal holes, and can reproduce their physical parameters. The main advantage of the FBP algorithm is that it is easy to understand and computationally efficient. Thus, it enables us to easily probe the inhomogeneous coronal electron density and temperature distribution of the solar corona.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
