The controlled production of a local hot spot in supercompressed deuterium + tritium fuel is examined in details. Relativistic electron beams (REB) in the MeV and proton beams in the few tens MeV energy range produced by PW-lasers are respectively considered. A strong emphasis is given to the propagation issues due to large density gradients in the outer core of compressed fuel. A specific attention is also paid to the final and complete particle stopping resulting in hot spot generation as well as to the interplay of collective vs. particle stopping at the entrance channel on the low density side in plasma target. Moreover, REB production and fast acceleration mechanisms are also given their due attention. Proton fast ignition looks promising as well as the wedged (cone angle) approach circumventing most of transport uncertainties between critical layer and hot spot. Global engineering perspectives for fast ignition scenario (FIS) driven inertial confinement fusion are also detailed. 


Electron-induced X-ray emission spectroscopy (EXES) combined with a semi-empirical electron scattering model, which describes the ionizations inside a material under electron irradiation, is used to determine the depth profile of shallow and ultra-shallow dopants in silicon. Two approaches are presented, depending on whether the shape of the profile is known or not. To test the method, X-ray intensities of implanted phosphorus atoms at various energies and doses in silicon are measured at a wide range of incident electron energies. From the experimental data combined with the model, the resulting profile parameters are determined. Comparison of secondary ion mass spectrometry and EXES associated with the electron scattering model shows that the proposed method is suitable for determining the shallow implant profiles with a depth resolution of one nanometer.

In this paper, we present a robust control strategy which is well adapted to parallel connected Forward/Buck converters. It is based on a non-linear controller which uses the advantages offered by sliding mode control and peak current techniques. This control offers fixed frequency control without using equivalent control calculation, synchronized ramp or variable hysteresis bandwidth. It also provides good robustness depending on variations of load parameters. A model of the system is developed which allows us to study the system independently of the module number that constitutes the structure. The controllability of the system is discussed and an analysis of the current behavior is provided.

The purpose of this work is the modeling and the analysis of fluid-wall interactions in a deformable cylindrical cavity which has one single orifice for inflow and outflow. The model is used to study the dynamical behavior of a non linear oscillatory coupled system. Indeed, the deformation of the cavity can be large, therefore the fluid contained inside the cavity changes greatly. Our analysis describes the behavior of the system according to its characteristic parameters. A dimensional analysis of the set of coupled equations describing the dynamical behavior of both the incompressible fluid and the cavity wall is performed. We show that such a behavior can be characterized by five dimensionless parameters. The equations are then solved by using the so-called time-staggered scheme which allows to integrate separately the equations describing the structure and the fluid dynamics during each time step. The fluid part is discretized by the finite difference method associated with an Arbitrary Lagrangian Eulerian formulation of the governing fluid dynamics equations and the structure part including the motion of the piston by a Runge-Kutta method. For an harmonic excitation, we show that after a transient phase, the response of the system is both anharmonic and periodic, with a fundamental period equal to that of the excitation. Moreover, we study the respective influence of the wall rigidity, the fluid viscosity and the inertia effects, for different magnitudes of the excitation. Using an approximation of the damping force associated with the viscous effects of the dynamical flow, we complete this study by showing how the system of equations can be decoupled.

To contribute to the existing knowledge of the hydrodynamic force exerted on a spherical particle placed in the axis of a cylinder, at small Reynolds numbers, the influence of the uniform and Poiseuille flows on the wall correction factor are numerically and asymptotically investigated. The Stokes and continuity equations are expressed in the stream function and vorticity formulation and are rewritten in an orthogonal system of curvilinear coordinates. These equations are solved using a finite differences method. The generation of the grid was carried out by the singularities method. The accuracy of the numerical code is tested through comparison with theoretical and experimental results. In both cases we numerically calculated the separate contributions of the pressure and viscosity forces. In concentrated regime these numerical calculations are in very good agreement with those obtained by asymptotic expansions. This analysis allowed us to show the prevalence of the pressure term over the viscosity one in the lubrication regime contrary to what happened for the dilute regime. All our numerical and asymptotical results compared with those of Bungay et al. (Int. J. Multiphase Flow 1, 25–56 (1973)) seem to give a response to this problem argued for a long time.