Surface Plasma Wave Produeced By Interaction Of Laser And Plasma

Surface plasma waves will significantly affect the subsequent mutual coupling of laser and plasma.Therefore,it is very important for the laser plasma physics fields,such as laser-driven fast ignition inertial confinement fusion,laser-driven particle acceleration,and laser propagation in plasma.In this paper,by using the all-electromagnetic large-scale plasma particle simulation program Opic 2.0,the formation of surface plasma waves and its dependence on related parameters of the ultra-short and ultra-strong laser entering the thin plasma target are studied.Besides,the effect of surface plasma waves for laser propagation through the thin high-density plasma target is studied.In the first half of this thesis,the research background and research content of laser plasma physics,as well as the related properties and applications of surface waves,is introduced.Then the dispersion relationship,wavelength and other characteristic lengths of surface plasma waves is derived,and the main algorithm of Opic2.0 is introduced.The finite particle cloud model,FDTD algorithm,and laser introduction method are briefly described.The main content of the second half is the simulation result of laser pulses incident on a thin plasma target.The strong laser excites surface plasma waves on the plasma surface.The surface waves can only propagate alone the surface and decay rapidly in the direction perpendicular to the surface.The simulations in this thesis include several parts:(1)The high-intensity laser is incident parallel to the double-layer plasma target.Previous experiments and theories have shown that surface plasma waves cannot be generated when the laser is incident on a single-layer plasma target in parallel,but with the use of a double-layer plasma target structure,that is,a thin plasma layer with a lower density in front of the high density target,can excite the surface plasma wave.Surface plasma waves cause electrons to leave the plasma surface to form a surface electron density distribution.In this paper,by observing the period,height and other parameters of the density distribution,such as the wavelength,formation and dissipation process of surface plasma waves are studied.(2)The high-intensity laser is incident on the double-layer plasma target obliquely.When the incident angle is in the range of 45°-80°,after increasing the incident angle,it is found that the expansion height of the electron density distribution also increases,while the density decreases.The expansion height is negatively related to the angle of incidence.The surface plasma wave propagates from the oblique incident center to both sides of the target,pushing the electron density to redistribute to form a dense zigzag structure.Increasing the density of the thin plasma layer can observe more obvious density stratification and zigzag structure.(3)Calculate the transmittance of the subsequent incident laser.The zigzag structure is similar to the surface grating structure,and has a certain increase in transmittance.This thesis gives the transmittance curve with the density of the thin plasma layer,and calculates the transmittance when the laser enters the plasma with sub-wavelength surface grating as a control.