Byrd J M, Hao Z, Martin M C, Robin D S, Sannibale F, Schoenlein R W, Zholents A A, Zolotorev M S
Ernest Orlando Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
Phys Rev Lett. 2006 Aug 18;97(7):074802. doi: 10.1103/PhysRevLett.97.074802.
We report the first observation of laser seeding of the storage-ring microbunching instability. Above a threshold bunch current, the interaction of the beam and its radiation results in a coherent instability, observed as a series of stochastic bursts of coherent synchrotron radiation (CSR) at terahertz frequencies initiated by fluctuations in the beam density. We have observed that this effect can be seeded by imprinting an initial density modulation on the beam by means of laser "slicing." In such a situation, most of the bursts of CSR become synchronous with the pulses of the modulating laser and their average intensity scales exponentially with the current per bunch. We present detailed experimental observations of the seeding effect and a model of the phenomenon. This seeding mechanism also creates potential applications as a high-power source of CSR at terahertz frequencies.
我们报道了对储存环微聚束不稳定性进行激光种子注入的首次观测结果。在高于阈值束流强度时，束流与其辐射的相互作用会导致一种相干不稳定性，表现为一系列太赫兹频率的相干同步辐射（CSR）随机爆发，这些爆发由束流密度的波动引发。我们观察到，通过激光“切片”在束流上施加初始密度调制，可以引发这种效应。在这种情况下，大多数CSR爆发与调制激光脉冲同步，并且它们的平均强度随每束电流呈指数增长。我们展示了种子注入效应的详细实验观测结果以及该现象的模型。这种种子注入机制还为太赫兹频率的高功率CSR源创造了潜在应用。
