Laser-ion acceleration via anomalous electron heating
Abstract
Using a kilojoule class laser, we demonstrate for the first time that high-contrast picosecond pulses are advantageous for ion acceleration. We show that a laser pulse with optimum duration and a large focal spot accelerates electrons beyond the ponderomotive energy. This anomalous electron heating enables efficient ion acceleration reaching 52 MeV at an intensity of 1.2X10^19 Wcm^-2. The proton energy observed agrees quantitatively with a one-dimensional plasma expansion model newly developed by taking the anomalous heating effect into account. The heating process is confirmed by both measurements with an electron spectrometer and a one-dimensional particle-in-cell simulation. By extending the pulse duration to 6 ps, 5% energy conversion efficiency to protons (50 J out of 1 kJ laser energy) is achieved with an intensity of 10^18-Wcm^-2. The present results are quite encouraging for realizing ion-driven fast ignition and novel ion beamlines.
Cite
@article{arxiv.1608.00341,
title = {Laser-ion acceleration via anomalous electron heating},
author = {A. Yogo and K. Mima and N. Iwata and S. Tosaki and A. Morace and Y. Arikawa and S. Fujioka and H. Nishimura and A. Sagisaka and T. Johzaki and K. Matsuo and N. Kamitsukasa and S. Kojima and H. Nagatomo and M. Nakai and H. Shiraga and M. Murakami and S. Tokita and J. Kawanaka and N. Miyanaga and K. Yamanoi and T. Norimatsu and H. Sakagami and S. V. Bulanov and K. Kondo and H. Azechi},
journal= {arXiv preprint arXiv:1608.00341},
year = {2016}
}
Comments
This paper has been withdrawn by the author to revise the theoretical model on the ion acceleration