3D multi-scale modelling of plasma-based seeded soft X-ray lasers

Abstract

Modelling plasma-based seeded soft X-ray lasers from the creation of the plasma to the propagation of a femtosecond high-order harmonic (HOH) seed throughout several millimetres of inhomogeneous plasma is a complex challenge. Different spatio-temporal scales from the hydrodynamic evolution of the plasma (hundreds of micrometres and nanoseconds) to the propagation of pulses through the plasma (millimetres and tens of picoseconds), electron collisions (picoseconds or even shorter) and the evolution of the envelope of the seeded HOH (tens of femtoseconds) must be tackled in order to fully understand these systems. In this paper, we will present the multi-scale computational paradigm that we have used to perform a full ab initio simulation of a dense, Ni-like Krypton plasma amplifier of soft X-rays. Results of the modelling and expected future applications will also be shown.

Amplification of HOH carrying orbital angular momentum in plasma-based amplifiers

“…Solved through the Dagon code [21], the computational structure required is considerably more complex, as it involves a multiscale and multiphysics problem, with characteristic time processes ranging from nanoseconds, such as plasma hydrodynamics, to femtoseconds, such as the dynamics of the amplified pulse. The structure involving different coupled codes can be consulted in [22]. Finally, this section also develops some of the post-processing tools used for the analysis of the amplified pulse, regarding OAM assessment and the influence of detrimental phenomena such as refraction.…”

“…This sum includes all levels capable of populating the levels involved in the laser transition. For krypton OFI amplifier plasmas, these rates have been calculated using a radiative-collisional code, OfiKinRad [23], since in this case plasma hydrodynamics can be decoupled from the pumping of Kr 8+ ions [22].…”

Spatio-temporal couplings for controlling group velocity in longitudinally pumped seeded soft X-ray lasers

“…Simulations have been performed using the DAGON 3D Maxwell-Bloch code 28,35 . The group velocity of the pump beam can be varied as an input parameter of this code, which models the full spatio-temporal structure of the amplification of high-order harmonics along the pulse propagation in a krypton plasma amplifier.…”

Towards soft X-ray imaging: results in plasma-based lasers and plenoptic imaging

“…In this chapter, an overview of the DAGON code is outlined, with the introduced improvements and conducted simulations, along with my contributions to the field resulting in the articles [130] and [101].…”

“…The 3D code DAGON, an update of the 1D DeepOne code, was developed to study the propagation regime of the HOH seed beam in plasma-based SXRLs. This simulation code accounts for and accurately describes the phenomena occurring when the HOH beam travels down the plasma channel, such as ASE, Rabi oscillations and, the most important case for study, the amplification of the seed beam [98], [52], [101].…”