Collimated particle acceleration by vortex laser-induced self-structured "plasma lens".

A micrometer-scale "plasma lens" self-constructed by the prepulse and main pulse of the Laguerre–Gaussian (LG) laser is realized to enhance the collimation and acceleration of proton beams in a target normal sheath field acceleration mechanism. Hydrodynamic FLASH and particle-in-cell simulations are carried out and find that a collimated proton source with beam divergence ∼2.7° is generated by the LG laser, which is smaller than the case driven by the traditional Gaussian laser. It demonstrates that the curved sheath field on the "plasma lens" plays an important role in the beam collimation. Such an approach considerably relaxes the constraints of complex design for the target fabrication and auxiliary laser pulse, opening new doors for high-repetition-rate collimated proton accelerations for innovative applications in upcoming high-repetition-rate petawatt laser systems. [ABSTRACT FROM AUTHOR]