Topic/Type: 1.4 Accelerators & Beams, Oral

3D Modeling of the amplification of a High-Order-Harmonics beam in a plasma created by OFI

A. Boudaa1, 3, B. Robillart1, G. Maynard1, B. Cros1, J. Ph. Goddet2, F. Tissandier2, S. Sebban2

1 Laboratoire de Physique des Gaz et des Plasma, Univ. Paris-Sud, F-91405 Orsay, France
2 Laboratoire d?Optique Appliqu?e (LOA), ENSTA-?cole Polytechnique, Chemin de la Huni?re, 91761 Palaiseau, France
3 Laboratoire de Physique et Chimie Quantique, Universit? M. Mammeri de Tizi-Ouzou, Hasnaoua 15000, Alg?rie

It has been experimentally demonstrated [1] that the amplification of a beam generated by High Order Harmonic (HOH) through a plasma created by Optical Field Ionization (OFI) can provide a soft-x-ray laser (SXRL) beam with interesting properties in terms of applications. In particular the generated SXRL beam has a larger energy and better coherence properties than the HOH beam.
A 3D modeling of the amplification and transport of the SXRL beam through the plasma has been developed in order to analyze the experimental data. It has been done by combining the following three codes : A 2D propagation code from which the properties of the plasma is determined following OFI by an intense infrared red laser beam with few tens of fs duration [2], a 0D kinetic code calculating the non-equilibrium dynamics of the atomic excited states inside the plasma [2] and a full 3D Maxwell-Bloch code determining the amplification and the transport of the SXRL signal inside the plasma.
Using our codes, several specific points relevant to the experiment have been examined in details. It concerns the collective heating of the plasma ions due to strong coupling [3], the spatial filtering effect of the amplifier due to its small ratio of transverse to longitudinal dimensions [1], the non-adiabatic character of the amplification in its early phase coming from the short duration of the injected HOH pulse and the apparition of Rabi type oscillations at the highest values of the intensities. The related results will be presented for krypton and xenon plasma.

[1] J. Ph. Goddet et al., Optics Letters 32, 1498 (2007).

[2] B. Cros, et al., Phys. Rev. A 73, 033801(2006).

[3] G. Maynard et al., Contrib. Plasma Phys. 47, 352 (2007).