Laser seeded electron beam filamentation in high intensity laser wakefield acceleration

In previous laser wakefield acceleration experiments, electron beam filamentation was observed due to the current filamentation instability, which occurred in laser-plasma interaction lengths greater than the laser depletion length [1]. Recent experiments using the HERCULES laser, with approximately 160TW, also showed the appearance of multiple electron beams observed consistently. Due to the laser's high intensity, and astigmatism in the focusing optics, localized hot spots in the laser profile before and after focus resulted in multiple wakefield generation. Through self-focusing in the wakefields, the laser pulse broke into individual filaments, which lead to the acceleration of multiple beamlets.