Transverse self-modulation of ultra-relativistic lepton beams in the plasma wakefield accelerator

TL;DR

This paper uses simulations to show how ultra-relativistic lepton bunches can self-modulate in plasma, creating strong wakefields and energy gains, with differences based on charge and potential for experimental testing.

Contribution

Demonstrates through simulations that long lepton bunches can be strongly self-modulated in plasma, producing high accelerating fields and energy gains, with insights into charge-dependent effects and experimental feasibility.

Findings

Self-modulation leads to wakefields >20 GV/m.

Particles can gain >10 GeV energy in meter-long plasmas.

Seeding suppresses hosing instability.

Abstract

The transverse self-modulation of ultra-relativistic, long lepton bunches in high-density plasmas is explored through full-scale particle-in-cell simulations. We demonstrate that long SLAC-type electron and positron bunches can become strongly self-modulated over centimeter distances, leading to wake excitation in the blowout regime with accelerating fields in excess of 20 GV/m. We show that particles energy variations exceeding 10 GeV can occur in meter-long plasmas. We find that the self-modulation of positively and negatively charged bunches differ when the blowout is reached. Seeding the self-modulation instability suppresses the competing hosing instability. This work reveals that a proof-of-principle experiment to test the physics of bunch self-modulation can be performed with available lepton bunches and with existing experimental apparatus and diagnostics.