The Numeircal Simulation Of Hot Electrons Energy Deposition In Dense Plasma Of Fast-ignition Precompressed Targets

As the reduction of fossil energy, increasing attention has been paid on searchingfor alternative clean energy. Comparing with the sustainable energy, such as the powerfrom wind and solar, fusion energy has some advantages. For example, its raw materialsare substantially stored, and the energy release is huge. As one major form of thecontrolled nuclear fusion, inertial confinement fusion (ICF) has aroused great concern.There are two main ways to achieve the ignition of ICF: center ignition and fast ignition.Fast ignition, which can lower the driving energy and reduce the hydrodynamicinstability, has become the focus of research in ICF. The energy deposition of the hotelectrons in dense deuterium-tritium (DT) plasmas of fast ignition targets, whichdominates the ignition of the nuclear fuel, has been a key issue of fast ignition.In this dissertation, the energy deposition of hot electrons in dense plasma ofprecompressed cryogenic DT targets is discussed in fast ignition initial confinementfusion. The electron transport and energy deposition are dominated by Coulombcollision and exciting plasma wave. The main content of the paper is as follows.1. The simulation model of the energy deposition has been developed. The energydeposition of the hot electrons around the target core is considered by the stoppingpower model. During the simulation, the contribution to energy loss by bremsstrahlung,self-field and Weibel instability is ignored. The continuous slowing down stoppingpower model has been combined with the more accurate relativistic differential crosssectional model to improve the certified models.2. Quantitative description of the energy deposition has been discussed. Themultiple scattering theory of Lewis is applied to calculate the spatial moment of theelectron distribution function. Considering the impact factor (i.e. approximates to theThomas-Fermi radius), the total path length and the mean penetration are obtainedusing continuous slowing down stopping power of electrons and the first-order spatialmoment of the electron distribution function. The longitudinal straggling and the beamblooming are obtained by the second-order spatial moment of the electron distributionfunction, which describing the dispersion of the hot electrons transport. 3. The impact of different physical parameters to energy deposition has beenshown. The effect of the physical parameters of plasma, such as the charge of ions,temperature and density on energy deposition is also discussed.