Exploratory Study Of Producing THz Coherent Synchrotron Radiation Based On Hefei Light Source

Terahertz(THz) radiation has a wide application prospect. This paper discusses the principle and possibility of producing THz radiation on Hefei Light Source(HLS), studies the method of generating coherent radiation on a non-coherent light source, like HLS, and proposes a preliminary scheme of obtaining avaliable THz coherent radiation on HLS.In this paper, we first study the dynamics of electrons in bunches which is excited by fast kicker magnet, and consider the impact of transverse nonlinearity and chro-maticity in the storage ring. The formation if a wavy beam with periodic structure is then investigated after introducing an ac sextupole.The effects of radiation damping and quantum excitation on the periodic structure of the wavy beam are also investigated. We introduce electromagnetic radiation theory, as the starting point of this paper, in detail. The calculation formula of the radiation spectrum of a single electron through a bending magnet and an undulator is given. Then, the coherent synchrotron and the coherent radi-ation characteristics and spectrum of the wavy beam are studied. Because coherent syn-chrotron radiation has extremely high power, in order to measure coherent synchrotron radiation on the bunch, the classic one-dimensional radiation wake theory is extended to the two-dimensional space. Based on a single electron wake calculation formula, the numerical calculation method is used to obtain the distribution of the radiation wake distribution in the wavy beam. The results show that when the excitation amplitude is comparable to the bunch longitudinal length, the radiation wake is obviously devi-ated from the one-dimensional radiation wake theory, and this distribution of the wake field is mainly determined by the modulation term. In our design, we introduced the ac sextupole,which will bring a strong non-linear effect. In order to investigate the ef-fect of this nonlinearity, the dynamics aperture is simulated. The results show that the dynamics aperture is still larger than the transverse size of the bunch. Even though the non-linear effect is strong, it is still within the acceptable rangle.The coherent radiation spectrum of HLS at 400MeV was calculated. The results show that when the DC chromaticity and AC chromaticity are 5 and the initial amplitude is 1 cm, the narrow-band THz synchrotron radiation with center frequency of 0.1491 THz can be generated.