Experimental study of electron beam guidance for rapid ignition of fusion targets

The work presented in this thesis is realised in the framework of the fast ignition of inertial confinement fusion for energy production. In this scheme the compression and the ignition phases are decoupled. During the second phase, the electron beam must propagate over 300 μm in the dense fuel before depositing its energy in the dense core and igniting the fusion reactions. The major problem of the scheme is related to the divergence of the electron beam while it crosses the dense matter. Among the different propositions to inhibit the electron divergence we consider here the schemes without cone that are based on the effect of magnetic collimation. In particular, A.P.L. Robinson and his co-authors [Phys. Rev. Lett. 100, 025002, 2008] suggested a simple way to control the electron beam divergence by using a sequence of two laser pulses. The first one creates a magnetic background favorable for the confinement of the electron beam resulting from the second pulse interaction. The validation of this scheme is the major goal of this thesis. We present, in this manuscript, the results of experimental studies and numerical modeling of the electron beam guiding with help of two consecutive laser pulses. The experiment was performed on the Vulcan facility at the Rutherford Appleton Laboratory at Didcot in UK, based on the proposal submitted by an international group of scientists in the framework of the European project for inertial fusion energy HiPER. This experiment allowed us to define a combination of laser and target parameters where the electron beam guiding takes place. The analysis of experimental data and numerical modelling is realised with the hydrodynamic code CHIC coupled to the charged particles transport module M1. The interpretation of the experimental results allowed us to explain the experimental data and the physical basis of guiding and to define the magnetic condition favorable to the electron beam guidance. (author)