Controlling fast electron beam divergence using two laser pulses
Abstract
This paper describes the first experimental demonstration of the guiding of a relativistic electron beam in a solid target using two co-linear, relativistically intense, picosecond laser pulses. The first pulse creates a magnetic field which guides the higher current fast electron beam generated by the second pulse. The effects of intensity ratio, delay, total energy and intrinsic pre-pulse are examined. Thermal and K{\alpha} imaging showed reduced emission size, increased peak emission and increased total emission at delays of 4 - 6 ps, an intensity ratio of 10 : 1 (second:first) and a total energy of 186 J. In comparison to a single, high contrast shot, the inferred fast electron divergence is reduced by 2.7 times, while the fast electron current density is increased by a factor of 1.8. The enhancements are reproduced with modelling and are shown to be due to the self-generation of magnetic fields. Such a scheme could be of considerable benefit to fast ignition inertial fusion.
Cite
@article{arxiv.1012.2029,
title = {Controlling fast electron beam divergence using two laser pulses},
author = {R. H. H. Scott and C. Beaucourt and H. -P. Schlenvoigt and K. Markey and K. L. Lancaster and C. P. Ridgers and C. M. Brenner and J. Pasley and R. J. Gray and I. O. Musgrave and A. P. L Robinson and K. Li and M. M. Notley and J. R. Davies and S. D. Baton and J. J. Santos and J. -L. Feugeas and Ph. Nicolaï and G. Malka and V. T. Tikhonchuk and P. McKenna and D. Neely and S. J. Rose and P. A. Norreys},
journal= {arXiv preprint arXiv:1012.2029},
year = {2013}
}