Simulated THz-powered high-energy electron bunch width short pulse duration. (a) Simulation of the condition with two-stage THz-powered modules. The first stage is for bunch compression with a peak field gradient of ~0.4 MV/m and sub-μJ THz energy. The second stage is for acceleration with a peak field gradient of ~280 MV/m and sub-mJ THz energy. (b) Simulated bunch length along the propagation direction.