Research On The Divergence And Temperature-Scaling Of Laser-driven Hot Electrons

Chirped-Pulse Amplification(CPA)technology makes it possible for laser pulse to reach ultra-high intensity,and theoretical research on laser plasma interaction and its appliances has been witnessing a sharp development through the decades.These researches have many promising and attractive applications on newly-developed particle acceleration,inertial confined fusion and so on.This dissertation mainly focuses on the research about the divergence of laser-driven fast electrons and temperature-scaling of hot electrons in magnetized plasma interaction with laser pulse through numerical simulation and theoretical analysis.In the introduction,research background about laser plasma interaction has been elaborated.Also,useful theoretical models of J × B heating,production of self-generated magnetic field and Weibel instability are presented.In the second chapter,we introduce the generally applied algorithms for particle push and solving electric magnetic field.Then,For the PIC routine EPOCH,ionization module,which is important in our research,is carefully introduced to lay a basis for further research.In the third chapter,we discuss the influence of field ionization effect on the divergence of laser-driven fast electrons through 2D3V PIC simulation.Theoretical analysis sharpens our knowledge on factors that affect the divergence of laser-driven hot electrons and we found that after the consideration of field ionization effect,strong self-generated magnetic field originating from Weibel instability in the pre-plasma region deflects the hot electrons a lot,thus causing an enlarged divergence in the ionzing targets.Meanwhile,it shows that target materials have little influence on the hot electron divergence.In the forth chapter,we study the temperature scaling of hot electrons in magnetized plasma interaction with lasers.Electron cyclotron resonance heating is carefully induced and through comparision with simulation data,we found that the temperature of hot electrons will be sharply strengthened under a specific external magnetic field strength,while deviation from the matched magnetic filed strength will harm the heating of electrons.