The effect of pre-plasma formation under nonlocal transport conditions for ultra-relativistic laser-plasma interaction

Abstract

Interaction of high-power lasers with solid targets is in general strongly affected by the limited contrast available. The laser pre-pulse ionizes the target and produces a pre-plasma which can strongly modify the interaction of the main part of the laser pulse with the target. This is of particular importance for future experiments which will use laser intensities above 10 21 W cm −2 and which are subject to the limited contrast. As a consequence the main part of the laser pulse will be modified while traversing the pre-plasma, interacting with it partially. A further complication arises from the fact that the interaction of a high-power pre-pulse with solid targets very often takes place under nonlocal transport conditions, i.e. the characteristic mean-free-path of the particles and photons is larger than the characteristic scale-lengths of density and temperature. The classical diffusion treatment of radiation and heat transport in the hydrodynamic model is then insufficient for the description of the pre-pulse physics. These phenomena also strongly modify the formation of the pre-plasma which in turn affects the propagation of the main laser pulse. In this paper nonlocal radiation-hydrodynamic simulations are carried out and serve as input for subsequent kinetic simulations of ultra-high intensity laser pulses interacting with the plasma in the ultra-relativistic regime. It is shown that the results of the kinetic simulations differ considerably whether a diffusive or nonlocal transport is used for the radiation-hydrodynamic simulations.

Lagrangian Magneto-Hydrodynamics Based On Curvilinear Finite Elements

“…Further analysis of the numerical properties of the scheme and verification on different physically relevant problems remains a topic of future work. While the application for multi-physics modelling of laser-target interaction in the context of pre-pulse effects and non-local transport [1,2] can benefit from the new numerical scheme definitely, the method is very general and can be applied in other areas of physics.…”

“…The problem of modelling magnetized fluids arises in many disciplines like plasma dynamics, microfluidics, astrophysics. Our interest lies mainly in the former, where the continuum plasma dynamics within the laser-target interaction encompasses the pre-pulse effects of ultra-intense laser pulses [1] or non-local radiation and electron heat transport [2,3]. However, the proposed numerical model can be applied to a wide variety of problems.…”

High-Order Curvilinear Finite Element Magneto-Hydrodynamics I: A Conservative Lagrangian Scheme

“…Altogether, the novel method can push the frontiers of research in ICF [1], astrophysics [5], prepulse effects of ultra-intense lasers [6,7] or laser ion acceleration beamlines [50,8,9,10] and other areas, where the Lagrangian approach is favored for a strong expansion/compression of the matter and a multi-dimensional treatment is needed. These applications can then benefit from the rapid convergence, flexibility of the mesh design and robustness of the method.…”

“…The boundary conditions are analogous to (7), where the conditions for the fields reduce to the transverse components only.…”

“…We are particularly interested in the Lagrangian approach, where the coordinate system follows the flow of the fluid. It is mostly favored in areas of modeling where the medium undergoes extreme compression or expansion like inertial confinement fusion [1,2], Z-pinches [3], supernovae collapses [4], cosmic jets [5], prepulse effects of ultra-intense lasers [6,7] or laser ion acceleration beamlines [8,9,10] as are explored at facilities like ELI Beamlines [11,12] and other multi-PW laser systems worldwide [13].…”