Runaway electrons (REs) in experimental advanced superconducting tokamak (EAST) typically have an energy level of tens of MeV. Synchrotron radiation images of REs contain a wealth of information, making it crucial to handle this data properly to uncover hidden features. We observed distinct synchrotron radiation images emitted by the REs at different time points throughout the discharges and the focus of our study was an Ohmic discharge characterized by an evident synchrotron pattern and weaker background radiation. This paper aims to verify the feasibility of utilizing the green function and regularization method to obtain the distribution function information of synchrotron radiation images on EAST. We reconstruct the radial density profile of the REs beam by assuming the monoenergetic nature of REs at different time points. We employ the Tikhonov regularization method for this purpose. The results indicate that the radial density profile of the REs beam follows a roughly Gaussian distribution. Moreover, the peak density of the REs beam shifts inward to the magnetic axis as time progresses, a behavior also observed in the experimental image. However, a good fit between the simulated and experimental images is not achieved for all time points. This discrepancy is likely due to the intervention of magnetic islands and the increased complexity of the distribution function in both radial and momentum spaces.
実験的先进超导托卡马克（EAST）中的逃逸电子（REs）通常具有数十MeV的能量水平。逃逸电子的同步辐射图像包含丰富的信息，因此正确处理这些数据以揭示隐藏特征至关重要。我们在放电过程中的不同时间点观测到了逃逸电子发射的明显不同的同步辐射图像，而本研究的重点是一种具有明显同步辐射图案和较弱背景辐射的欧姆放电。本文旨在验证利用格林函数和正则化方法从EAST同步辐射图像中获取分布函数信息的可行性。我们通过假设逃逸电子在不同时间点具有单能特性，重建了逃逸电子束的径向密度分布。为此，我们采用了Tikhonov正则化方法。结果表明，逃逸电子束的径向密度分布大致呈高斯分布。此外，随着时间推移，逃逸电子束的峰值密度向磁轴方向移动，这一行为也在实验图像中得到了观察。然而，并非所有时间点的模拟图像与实验图像都能实现良好拟合。这一差异可能归因于磁岛的影响以及分布函数在径向和动量空间中复杂性的增加。