1.053μm激光在腔靶中产生的非线性过程

NONLINEAR PROCESSES FROM INTERACTION OF 1.053μmLASER WITH HOHLRAUM TARGETS

  • 摘要: 波长1.053μm、脉宽约1ns、能量300~600J激光在亚毫米的腔靶中可以产生十分丰富的非线性过程。我们直接测量了受激Brillouin散射、受激Raman散射:通过谐波间接测量了共振吸收、离子声衰变和双等离子体衰变。其中受激Brillouin散射和受激Raman散射是腔靶中的主要非线性过程,它散射掉约40%的入射光能量。激光激发的电子等离子体波是产生超热电子的根源,产生电子等离子体波的非线性过程是受激Raman散射、双等离子体衰变、共振吸收和离子声衰变。其中受激Raman散射是激发电子等离子体波的主要过程,它产生约占入射激光能量10%的超热电子。各非线性过程发射的光谱与激光参数和等离子体状态有密切关系,仔细测量和研究这些谱的特性可以获得等离子体温度、密度的信息。

     

    Abstract: Abundant nonlinear processes may be producd in submillimeter size hohlraumtargets by 1.053μm laser light with duration of 1ns and energy of 300~600J.In experiments,Stimulated Brillouin Scattering(SBS)and Stimulated Raman Scattering(SRS)were directly meas-ured, and Resonance Absorption(RA),Two Plasmon Decay(TPD),and Ion Acoustic Decay(IAD)were observed indirectly.The experimental results show that SBS and SRS are the domi-nant nonlinear processes in cavity,they can scatter about 40% of the incident laser energy. Elec-tron plasma wave stimulated by nonlinear processes such as SRS, TPD,RA,and IAD is thesources of suprathermal electron generation. Our research indicates that SRS is the chief processfor electron plasma wave generation in hohlraum target,and it can produce suprathermalelectrons with a total energy about 10% of incident laser energy.Because spectra of nonlinearprocesses scattering light have a closely ralation with plasma state.We can obtain imformationabout plasma state through intensive measure and analysis to thesc spectra of scattering light.

     

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