Eur. Phys. J. D (2013) 67: 205
https://doi.org/10.1140/epjd/e2013-40362-4

Regular Article

Polar direct drive illumination uniformity provided by the Orion facility

¹ Centre de Mathématiques et de Leurs Applications, ENS Cachan and CNRS, 61 avenue du Président Wilson, 94235 Cachan Cedex, France
² CEA, DIF, 91297 Arpajon Cedex, France
³ AWE plc, Aldermaston, Reading, Berkshire, RG7 4PR, United Kingdom
⁴ ETSI Aeronáuticos, Universidad Politécnica de Madrid, 28040 Madrid, Spain

^a e-mail: mauro.temporal@hotmail.com

Received: 17 June 2013
Received in final form: 25 July 2013
Published online: 10 October 2013

Abstract

The ten long-pulse laser beams of the Orion facility have been considered as a direct driver for the irradiation of a spherical capsule. The intrinsic root-mean-square illumination non-uniformity σ₀ has been evaluated assuming circular and elliptical super-Gaussian laser intensity profiles. Calculations accounting for nominal uncertainties in power imbalance, pointing error and target positioning have shown a degradation of the irradiation uniformity. Non-uniformity of the irradiation as a function of the capsule radius has been calculated and it has been shown that the use of the polar direct drive technique significantly improves the quality of the irradiation. Finally, it is found that an elliptical focal shape provides better symmetry results in comparison to circular ones, whilst the laser-capsule coupling is reduced.