Study On The Nonlinear Propagation Properties Of An Intense Laser Pulse In Partially Stripped Plasma

With the development of laser-plasma interaction technology, many new researchareas in strong field physics have opened up in the1990s, such as high-orderharmonic generation, laser-driven accelerators and advanced laser-fusion schemes.The nonlinear process during laser pulse propagation is inevitable, and it has morevalue about the influence in partially stripped, so the study on the nonlinearpropagation properties of an intense laser pulse in partially stripped plasma isessential.In this dissertation author has researched mainly two topics of intense laserinteracting with partially stripped plasma. The first is the propagation properties of anintense laser pulse in partially stripped plasma, and the second, the propagation of ashort laser pulse in partially stripped plasma. Four works have been completed and theresults are summarized as follows:1. In the presence of relativistic, wakefield driven by the ponderomotive forceand nonlinear polarization effects, the propagation characteristics of an intense shortlaser pulse in a partially stripped plasma are investigated. The evolution equation ofthe laser spot size is derived by using variational technique. The matched parametersof laser and plasma for propagation with constant spot size are identified by using thenonlinear dynamics. It is found that the laser focusing is enhanced in partially strippedplasma as compared to fully ionized plasma and also by the wakefield effects. Thelaser intensity for focusing dominates over the plasma density in partially strippedplasma.2. In the presence of wakefield, relativistic self-focusing, and polarizationnonlinearities, the propagation characteristics of a short laser pulse in partiallystripped plasma are investigated. The coupled evolution equations of the laser spotsize and the pulse length are derived by using variation technique, analyzing theeffects of the transverse wakefield(TWF) and longitudinal wakefield(LWF) on thepropagation of a short laser pulse in partially stripped plasma. It is found that the laserpulse can be allowed to propagate in patitally stripped plasma only when a certainrelation for laser parameters and plasma parameters is satisfied. The evolution of thepulse length should be considered in analyzing the propagation of the laser pulse inpatitally stripped plasma. The laser focusing is enhanced in partially stripped plasmaas compared to fully ionized plasma and also by the wakefield effect. The LWF hasaffected the laser focusing enhanced efficiently. The results may be significanttheoretically to the mechanism of ionization-induced injection and acceleration by anintense laser pulse.