Positron acceleration by terahertz wave and electron beam in plasma channel

We present a scheme of positron acceleration by intense terahertz (THz) wave together with the driving large-charge electron beam in a plasma channel. The THz wave rapidly evolves into a transversely uniform acceleration field and a weakly focusing/defocusing lateral field in the channel. The THz wave is partially formed with the scheme of coherent transition radiation when the electron beam goes through a metal foil and partially because of the wakefield in the plasma channel. The electron beam continuously supplies energy to the THz wave. Such a field structure offers the feasibility of long-distance positron acceleration while preserving beam quality. By two-dimensional simulations, we demonstrate the acceleration of positrons from initial 1 GeV to 126.8 GeV with a charge of similar to 10 pC over a distance of 1 m. The energy spread of accelerated positrons is 2.2%. This scheme can utilize the electron beam either from laser-driven or conventional accelerators, showing prospects towards high-quality and flexible THz-driven relativistic positron sources of similar to 100 GeV.

Automated summary

We propose a scheme for positron acceleration using intense terahertz (THz) waves and a large-charge electron beam in a plasma channel. The THz wave evolves into a transversely uniform acceleration field and a weakly focusing/defocusing lateral field in the channel. The THz wave is generated through coherent transition radiation as the electron beam passes through a metal foil, as well as the wakefield in the plasma channel. The electron beam continuously supplies energy to the THz wave. This scheme allows for long-distance positron acceleration while maintaining beam quality, and simulations demonstrate the acceleration of positrons from 1 GeV to 126.8 GeV over a 1 m distance with a charge of approximately 10 pC and energy spread of 2.2%. The scheme can utilize electron beams from laser-driven or conventional accelerators, offering prospects for high-quality and flexible THz-driven relativistic positron sources of approximately 100 GeV.