Publications by authors named "N Nakanii"
By employing the stabilizer in the supersonic gas nozzle to produce the plasma density profile with a sharp downramp, we have experimentally demonstrated highly stable electron beam acceleration based on the shock injection mechanism in laser wakefield acceleration with the use of a compact Ti:sapphire laser. A quasi-monoenergetic electron beam with a peak energy of 315 MeV ± 12.5 MeV per shot is generated.
View Article and Find Full Text PDFLaser wakefield acceleration, as an advanced accelerator concept, has attracted great attentions for its ultrahigh acceleration gradient and the capability to produce high brightness electron bunches. The three-dimensional (3D) density serves as an evaluation metric for the particle bunch quality and is intrinsically related to the applications of an accelerator. Despite its significance, this parameter has not been experimentally measured in the investigation of laser wakefield acceleration.
View Article and Find Full Text PDFThe sharp density down-ramp injection (shock injection) mechanism produces the quasi-monoenergetic electron beam with a bunch duration of tens of femtoseconds via laser wakefield acceleration. The stability of the accelerated electron beam strongly depends on the stability of the laser beam and the shock structure produced by the supersonic gas nozzle. In this paper, we report the study of a newly designed modular supersonic nozzle with a flexible stilling chamber and a converging-diverging structure.
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- Laser wakefield acceleration (LWFA) is gaining global interest due to its promising potential to match classical accelerators, but challenges in stability and reliability hinder its widespread use.
- The study investigates how controlling laser wavefronts, particularly through introducing aberrations, affects electron beam characteristics in an LWFA accelerator, revealing that complex wavefronts can outperform the traditionally accepted Gaussian distribution.
- Findings demonstrate a clear relationship between different input wavefronts and the stability, acceleration, and injection of electron beams, suggesting improvements in laser tuning could enhance control over LWFA-generated electrons.
Over the past century, understanding the nature of shock compression of condensed matter has been a major topic. About 20 years ago, a femtosecond laser emerged as a new shock-driver. Unlike conventional shock waves, a femtosecond laser-driven shock wave creates unique microstructures in materials.
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