Particle Simulation Of Fast Ignition In Laser Cone Target Interactions And Electron Transport

High intense laser plasma interaction is one of the key problems in laser inertial confinement fusion. In this thesis, we studied the generation of relativistic electrons in the high intense laser plasma interactions and the transport of relativistic electrons in dense plasma. We study these problems by using two and three dimensional PIC(Particle-In-Cell) code and theoretical analysis.We researched the laser light propagation in the conical target by using three dimensional PIC code. It is found that the existence of under-dense plasma in the conical target affects the light propagation and the generation of relativistic electrons. The laser light can be focused at the tip of cone and its intensity increases up to tens of times in the focal spot. There is a strong quasi-static magnetic field on the surface of conical target, and part of the relativistic electrons move along the surface to the tip of conical target. The existence of under-dense plasmas in the inner of conical target can enhance the number of relativistic electrons.We also used two and three dimensional PIC code studying the relativistic electrons transport in dense plasmas. And we observed the current beam filament and coalesce by using both three and two dimensional PIC codes. In the two dimensional simulations, we put forward the Delta equilibrium solution of current density and pointed out the transition of Bennett equilibrium to the Delta equilibrium is the current of the beam carried. When the beam current less than the Alfven limit, the equilibrium is Bennett type. On the contrary, when the beam current exceeds the Alfven limit, the equilibrium is Delta type. D.A.Hammer and N. Rostoker provided a balance solution of electron beam in 1970[ Phys. Fluids, pp1831-1850, (1970 ) ]; we also compared the similarity and differences.