Plasma has been proven to be a powerful medium which can provide coherent radiation across a wide wavelength from THz, infrared to ultraviolet and even X-ray, which have promising applications in cosmology, chemistry, biomedical science, and other fields. A far-field time-domain radiation calculation code (FaTiDo) is developed based on the Liénard-Wiechert potential[1, 2], which can calculate the collective radiation with the information of the relativistic macro-electrons in the particle-in-cell (PIC) simulation. It has several advantages over PIC in simulating radiation: (1) it provides far-field radiation results that can be compared with experiment results directly; (2) it is not affected by numerical noise and dispersion; (3) it can simulate radiation with very high temporal resolution. Here, we show three typical cases of radiation simulation using FaTiDo, including: γ-ray generation via inverse nonlinear Thomson scattering [3], THz radiation production through laser interaction with positive-gradient plasma [4], and high-order harmonic generation via the plasma mirror mechanism. New phenomena are found with this new code. Our code introduces a novel method for coherent radiation simulation, which may offer unique benefits for certain research applications.
 

plasma,time-domain radiation,calculation code,coherent radiation