Asymptotic Scaling Laws for Imploding Thin Fluid Shells

Scaling laws governing implosions of thin shells in converging flows are established by analyzing the implosion trajectories in the A, M≫ parametric plane, where A is the in-flight aspect ratio, and M is the implosion Mach number. Three asymptotic branches, corresponding to three implosion phases, are identified for each trajectory in the limit of A, M≫1. It is shown that there exists a critical value γcr = 1 + 2/ν (ν= 1, 2 for, respectively, cylindrical and spherical flows) of the adiabatic index gamma, which separates two qualitatively different patterns of the density buildup in the last phase of implosion. The scaling of the stagnation density ρs and pressure Ps with the peak value M0 of the Mach number is obtained. ©2002 The American Physical Societ

Absorption of VUV-FEL Radiation in Warm Dense Matter

The interaction of ultra-intense 50 fs VUV-beams with solid-density metal and plasma targets has been simulated, solving Maxwell$'$s equations in one-dimensional geometry. An explicit dielectric function is derived describing photo-ionization in addition to collisional absorption by conduction electrons. As an example, heating of thin aluminum foils up to electron temperatures of 450 eV is discussed, including results on emission spectra during and after the heating. The simulations correspond to experiments now in progress at DESY in Hamburg, using the new VUV Free Electron Laser

The physics of inertial fusion: beam plasma interaction, hydrodynamics, hot dense matter

(From Oxford Scholarship Online) The book is devoted to targets for nuclear fusion by inertial confinement and to the various branches of physics involved. It first discusses fusion reactions and general requirements for fusion energy production. It then introduces and illustrates the concept of inertial confinement fusion by spherical implosion, followed by detailed treatments of the physics of fusion ignition and burn, and of energy gain. The next part of the book is mostly devoted to the underlying physics involved in inertial fusion, and covers hydrodynamics, hydrodynamic stability, radiative transport and equations-of-state of hot dense matter, laser and ion beam interaction with plasma. It discusses different approaches to inertial fusion (direct-drive by laser, indirect-drive by laser or ion beams), including recent developments in fast ignition. The goal of the book is to give an introduction to this subject, and also to provide practical results even when derived on the basis of simplified models

Pair and γ-photon production from a thin foil confined by two laser pulses

Electron-positron and γ-photon production by high-intensity laser pulses is investigated for a special target geometry, in which two pulses irradiate a very thin foil (10-100 mn < skin depth) with same intensity from opposite sides. A stationary solution is derived describing foil compression between the two pulses. Circular polarization is chosen such that all electrons and positions rotate in the plane of the foil. We discuss the laser and target parameters required in order to optimize the γ photon and pair production rate. We find a γ- photon intensity of 7 x 1027/sr s and a positron density of 5 x 1022/cm3 when using two 330 fs, 7 x 1021W/cm2 laser pulses