The effects of the nonlinear polarization in a partially stripped plasma on stimulated Brillouin scattering (SBS) process of a strong laser are discussed. A set of nonlineax mode coupling equations and the linear grow...The effects of the nonlinear polarization in a partially stripped plasma on stimulated Brillouin scattering (SBS) process of a strong laser are discussed. A set of nonlineax mode coupling equations and the linear growth rate of SBS instability is derived, respectively. When the intensity of an incident laser Io > 10^(17) W/cm^2, the third order susceptibility X(3) will reduce the above mentioned linear growth rate enormously. If taking the maximum value of the second order susceptibility X(2), the growth rate may be decreased observably when Io > 10_^(14)W/cm2. Furthermore, the nonlinear susceptibility can affect the nonlinear evolution of SBS much extensively.展开更多
The laser pulse modulation instabilities in partially stripped plasma were discussed based on the phase and group velocities of the laser pulse and the two processes that modulation instabilities excited. The excitati...The laser pulse modulation instabilities in partially stripped plasma were discussed based on the phase and group velocities of the laser pulse and the two processes that modulation instabilities excited. The excitation condition and growth rate of the modulation instability were obtained. It was found that the positive chirp and competition between normal and abnormal dispersions play important roles in the modulation instability. In the partially stripped plasma, the increased positive chirp enhances the modulation instability, and the dispersion competition reduces it.展开更多
Based on the dispersion relation of intense laser pulse propagating in gradually ionized plasma, this paper discusses the frequency modulation induced by ionization of an ultra-short intense laser pulse interacting wi...Based on the dispersion relation of intense laser pulse propagating in gradually ionized plasma, this paper discusses the frequency modulation induced by ionization of an ultra-short intense laser pulse interacting with a gas target. The relationship between the frequency modulation and the ionization rate, the plasmas frequency variation, and the polarization of atoms （ions） is analysed. The numerical results indicate that, at high frequency, the polarization of atoms （ions） plays a more important role than plasma frequency variation in modulating the laser frequency, and the laser frequency variation is different at different positions of the laser pulse.展开更多
文摘The effects of the nonlinear polarization in a partially stripped plasma on stimulated Brillouin scattering (SBS) process of a strong laser are discussed. A set of nonlineax mode coupling equations and the linear growth rate of SBS instability is derived, respectively. When the intensity of an incident laser Io > 10^(17) W/cm^2, the third order susceptibility X(3) will reduce the above mentioned linear growth rate enormously. If taking the maximum value of the second order susceptibility X(2), the growth rate may be decreased observably when Io > 10_^(14)W/cm2. Furthermore, the nonlinear susceptibility can affect the nonlinear evolution of SBS much extensively.
基金Project supported by the National Natural Science Foundation of China （Grant No 10276002）.
文摘The laser pulse modulation instabilities in partially stripped plasma were discussed based on the phase and group velocities of the laser pulse and the two processes that modulation instabilities excited. The excitation condition and growth rate of the modulation instability were obtained. It was found that the positive chirp and competition between normal and abnormal dispersions play important roles in the modulation instability. In the partially stripped plasma, the increased positive chirp enhances the modulation instability, and the dispersion competition reduces it.
基金Project supported by the National Science Foundation of China （Grant Nos 10574010 and 10276002） and by Specialized Research Fund for the Doctoral Program of Higher Education （SRFDP） of China （Grant No 20050005016）
文摘Based on the dispersion relation of intense laser pulse propagating in gradually ionized plasma, this paper discusses the frequency modulation induced by ionization of an ultra-short intense laser pulse interacting with a gas target. The relationship between the frequency modulation and the ionization rate, the plasmas frequency variation, and the polarization of atoms （ions） is analysed. The numerical results indicate that, at high frequency, the polarization of atoms （ions） plays a more important role than plasma frequency variation in modulating the laser frequency, and the laser frequency variation is different at different positions of the laser pulse.
