Generally, turn-to-turn fluctuations of synchrotron radiation power in a storage ring depend on the 6D phase-space distribution of the electron bunch. This effect is related to the interference of fields radiated by different electrons. Changes in the relative electron positions and velocities inside the bunch result in fluctuations in the total emitted energy per pass in a synchrotron radiation source. This effect has been previously described assuming constant and equal electron velocities before entering the synchrotron radiation source. In this paper, we present a generalized formula for the fluctuations with a non-negligible beam divergence. Further, we corroborate this formula in a dedicated experiment with undulator radiation in the Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab. Lastly, possible applications in beam instrumentation are discussed.

中文翻译：

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起伏器辐射功率噪声的测量以及与初始计算的比较

通常，存储环中同步加速器辐射功率的匝间波动取决于电子束的6D相空间分布。这种效应与不同电子辐射的场的干扰有关。束内相对电子位置和速度的变化导致同步加速器辐射源中每次通过的总发射能量发生波动。前面已经描述了这种效应，假设在进入同步加速器辐射源之前电子速度恒定且相等。在本文中，我们提出了具有不可忽略的光束发散的波动的广义公式。此外，我们在费米实验室的可积分光学测试加速器（IOTA）存储环中使用起伏器辐射进行的专用实验中，证实了该公式。最后，