Electron Beam Acceleration Driven by Self-Generated Cherenkov Terahertz Pulse

Using a high-intensity terahertz (THz) pulse to accelerate particles holds a promising approach for the miniaturization of particle accelerators. Here, we propose a novel THz-driven particle acceleration scheme, which utilizes a Cherenkov THz pulse generated by an electron bunch to accelerate particles within the bunch, without resorting to any externally driven sources. A high-intensity Cherenkov THz pulse is first generated, as a high-charge electron bunch moves through the bunch channel in a dielectric axicon and is then reflected by the lateral face of the axicon, forming a focused THz pulse in another dielectric axicon downstream, whereby part of the original electron bunch catches the THz pulse and is accelerated for a relatively large length via the inverse Cherenkov (ICR) effect. The acceleration gradient is determined by the initial bunch charge, which can be higher than 40 MV/m, as the bunch charge is greater than 10 nC. This is an all-dielectric accelerator with simplified equipment, which affords a promising option for the development of compact and even table-top accelerators.