Showing papers by "David Neely published in 2008"
TL;DR: In this article, the authors investigated the properties of high energy protons accelerated during ultraintense, picosecond laser-irradiation of thin foil targets as a function of preplasma expansion at the target front surface.
Abstract: The properties of beams of high energy protons accelerated during ultraintense, picosecond laser-irradiation of thin foil targets are investigated as a function of preplasma expansion at the target front surface. Significant enhancement in the maximum proton energy and laser-to-proton energy conversion efficiency is observed at optimum preplasma density gradients due, to self-focusing Of the incident laser pulse. For very long preplasma expansion, the propagating laser pulse is observed to filament, resulting in highly uniform proton beams, but with reduced flux and maximum energy.
107 citations
24 Jun 2008
TL;DR: In this paper, an electrostatic focussing field generated in the confined region of a suitably shaped structure attached to the proton generating foil is exploited to reduce the divergence of the laser driven MeV proton beams.
Abstract: Significant reduction of inherent large divergence of the laser driven MeV proton beams is achieved by strong (of the order of 10(9) V/m) electrostatic focussing field generated in the confined region of a suitably shaped structure attached to the proton generating foil The scheme exploits the positively charging of the target following an intense laser interaction Reduction in the proton beam divergence, and commensurate increase in proton flux is observed while preserving the beam laminarity The underlying mechanism has been established by the help of particle tracing simulations Dynamic focussing power of the lens, mainly due to the target discharging, can also be exploited in order to bring up the desired chromaticity of the lens for the proton beams of broad energy range