Collisional shock waves induced by laser radiation pressure

Abstract

The formation of a collisional shock wave by the light pressure of a short-laser pulse at intensities in the range of 1018–1023 W/cm2 is considered. In this regime the thermodynamic parameters of the equilibrium states, before and after the shock transition, are related to the relativistic Rankine–Hugoniot equations. The electron and ion temperatures associated with these shock waves are calculated. It is shown that if the time scale of energy dissipation is shorter than the laser pulse duration a collisional shock is formed. The electrons and the ions in the shock-heated layer may have equal or different temperatures, depending on the laser pulse duration, the material density and the laser intensity. This shock wave may serve as a heating mechanism in a fast ignition scheme.

Shockwave and spallation in silver and other materials by sub‐ns laser pulse at 1016 W/cm2 intensity

“…Finally, the pressure jump, Δ p , across the shockwave in Ag target can be calculated from Equation (8), assuming the shockwave radius corresponding to that of 1 ns and the parameter Y 5 ( γ )/( γ + 1) = 0.25, as reported in the literature [ 15,30 ] : $$$$ \Delta p=\frac{8}{25}\left(\frac{E}{{r_s}^3}\right)\left[{Y}^5\left(\gamma \right)/\left(\gamma +1\right)\right]=0.32\cdot \left[100\frac{J}{{\left(100\cdot {10}^{-6}\right)}^3{m}^3}\right]\cdot 0.25=8\times {10}^{12}\ Pa $$$$ …”

“…Finally, the pressure jump, Δp, across the shockwave in Ag target can be calculated from Equation ( 8), assuming the shockwave radius corresponding to that of 1 ns and the parameter Y 5 (𝛾)/(𝛾 + 1) = 0.25, as reported in the literature [15,30] :…”

“…Certainly the pressure jump, Δp, across the shockwave in Ag target can be calculated from Equation (8), assuming the shockwave radius of 2 mm, corresponding to the target thickness, and the parameter Y 5 (𝛾)/(𝛾 + 1) = 0.25, as reported in the literature [15,30] : A value much higher than the compressive strength of silver of 300 MPa. [34] This shockwave pressure is higher that the compressive strength of many used materials but minor of that of Ge and Ta, materials in which we have not shown deformation after the laser shot.…”

Shocks and solitons in collisional dense laser produced plasmas

“…The various mechanisms involved in laser plasma interactions are (i) collisions, (ii) ponderomotive force, and (iii) relativistic effects [1]. For higher laser intensities, ponderomotive force plays a leading role in producing solitary profiles, shocks, double layers or other structures depending on various plasma conditions [2]. Several authors have investigated the formation of these nonlinear waves in various acoustic modes in the weak or completely nonlinear regimes [3,4].…”

“…And experimentally, converging shock front formations were observed when spherical targets were irradiated by an ultra short high intensity laser pulse [46]. Studies incorporating collisions show that a collisional shock wave is formed if the time scale of energy dissipation is shorter than the laser pulse duration [2]. The collision between the plasma particles can cause dissipation in the plasma system which influences a lot the propagation dynamics of nonlinear waves.…”