分类: 光学 >> 量子光学 提交时间: 2023-02-19
摘要: The overlapping of multiple beams is common in inertial confinement fusion (ICF), making the collective stimulated Brillouin scattering (SBS) with shared ion acoustic wave (IAW) potentially important because of the effectively larger laser intensities to drive the instability. In this work, based on a linear kinetic model, an exact analytic solution for the convective amplification of SBS with the shared IAW modes stimulated by two overlapped beams is presented. From this solution, effects of the wavelength difference, crossing angle, polarization states, and finite beam overlapping volume of the two laser beams on the shared IAW modes are studied. It is found that a wavelength difference of several nanometers between the laser beams has negligible effects, except for a very small crossing angle about one degree. However, the crossing angle, beam polarization states, and finite beam overlapping volume can have significant influences on the shared IAW modes. Furthermore, the out-of-plane modes, in which the wavevectors of daughter waves lie in the different planes from the two overlapped beams, are found to be important for certain polarization states and crossing angles of the laser beams with the finite beam overlapping volume. This work is helpful to comprehend and estimate the collective SBS with shared IAW in ICF experiments.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: The vacancy-type defects induced by co-implantation of He and H ions in China Low Activation Martensitic (CLAM) steel at room temperature were investigated with a variable-energy position beam Doppler broadening spectra (DBS). The co- implantation contained two patterns: one was implanted by He ions firstly, and then followed by H-ions implantation; the other was implanted by H ions in the first place, after that followed by He-ions implantation. The S parameters of implanted samples became larger than un-implanted one under different implantation fluences, and the S parameters of pre-implanted H were larger than pre-implanted He regardless of fluence. The difference of S parameters between pre-implanted H and He decreased with increasing fluence. He-H-vacancy complex is the reason that the S parameter of pre-implanted H is higher than pre-implanted He