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.

中文翻译：

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滤波反投影算法在太阳旋转断层扫描中的应用

太阳旋转断层扫描（SRT）是重建三维日冕物理参数的重要方法。在这里，我们提出了一种将滤波反投影 (FBP) 算法应用于 SRT 的方法。由于太阳极紫外 (EUV) 观测存在几个问题，特别是由于隐藏在太阳后面的日冕背面无法观测而导致数据丢失导致的问题，因此 FBP 算法通常不适合 SRT。我们开发了一种生成修正正弦图的方法，该方法解决了阻塞问题。修改后的正弦图是通过将太阳动力学天文台 (SDO) 上的大气成像组件 (AIA) 观测到的两个相对位置的 EUV 数据结合起来生成的。我们在 2019 年 2 月生成了大约一个月的修正正弦图，并在静态假设下重建了三维日冕。为了获得电晕的物理参数，我们采用了 DEM 反演方法。我们通过将重建数据与观察到的 EUV 图像、电子密度模型、先前对电子温度的研究和观察到的日冕图像进行比较，用修正的正弦图测试了 FBP 算法的性能。结果表明，FBP算法对亮区和冕洞进行了合理的重构，可以再现它们的物理参数。FBP算法的主要优点是易于理解且计算效率高。因此，