A Magnetic Compression method for sub-THz electron beam generation from RF freqencies

Current THz electron sources struggle with low energy gain and device miniaturization. We propose a magnetic compression method designed for relativistic electrons to perform post-compression on the beam from radiofrequency accelerators, to produce sub-THz electron beam with exceptionally high energy ($>1$ J). Through simulation studies, we longitudinally compress a relativistic electron beam with energy of 60 MeV and frequency of 3 GHz across a time span of 24 ns, yielding an electron pulse train at a 0.1 THz. The compressed beam exhibits a pulse width of 0.8 ns, a total charge of 24 nC, and an energy of 1.4 J, providing a new potential for ultra-high-energy THz electron beams generation.