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arXiv · 1012.2029

Controlling fast electron beam divergence using two laser pulses

R. H. H. Scott·C. Beaucourt·H. -P. Schlenvoigt·K. Markey·K. L. Lancaster·C. P. Ridgers·C. M. Brenner·J. Pasley·R. J. Gray·I. O. Musgrave·A. P. L Robinson·K. Li·M. M. Notley·J. R. Davies·S. D. Baton·J. J. Santos·J. -L. Feugeas·Ph. Nicolaï·G. Malka·V. T. Tikhonchuk·P. McKenna·D. Neely·S. J. Rose·P. A. Norreys
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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.

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R. H. H. Scott, C. Beaucourt, H. -P. Schlenvoigt, K. Markey, K. L. Lancaster, C. P. Ridgers, C. M. Brenner, J. Pasley, R. J. Gray, I. O. Musgrave, A. P. L Robinson, K. Li, M. M. Notley, J. R. Davies, S. D. Baton, J. J. Santos, J. -L. Feugeas, Ph. Nicolaï, G. Malka, V. T. Tikhonchuk, P. McKenna, D. Neely, S. J. Rose, P. A. Norreys. 2010-12-09. Controlling fast electron beam divergence using two laser pulses. https://doi.org/10.1103/physrevlett.109.015001

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