标题： 通过调整激光等离子体参数控制交叉束能量传输 显示英文标题

标题： Control of cross-beam energy transfer through laser-plasma parameter adjustment

摘要： 通过分析理论和二维模拟，研究了两束激光之间的交叉束能量转移（CBET），特别关注其在不同激光等离子体条件下从几百皮秒到一纳秒时间尺度上的线性和非线性演化。 基于由两束激光驱动的受激布里渊散射的色散关系，我们得到了CBET发生的激光频率差范围。 在非线性区域，离子声波（IAW）的高次谐波导致高激光强度下的饱和水平降低（$I\gtrsim 10^{15}\,\mathrm{W/cm^2}$）。 谐波IAW的波破裂导致CBET的第二次增长和最终饱和。 在低强度下，线性饱和水平随时间缓慢变化。 与高斯光束相比，带有斑点的平滑激光可以通过减少有效重叠区域来减轻CBET的饱和水平。 由于离子捕获引起的IAW频率降低，最大能量转移出现在略小于线性匹配条件的频率差处。 我们发现非线性行为对激光强度、频率差、电子密度和离子温度敏感。 总能量转移速率随着激光强度近似线性增加，强调了其在CBET控制中的关键作用。 显示英文摘要

摘要： Cross-beam energy transfer (CBET) between two lasers is investigated through both analytical theory and two-dimensional simulations, with particular attention to its linear and nonlinear evolution under various laser-plasma conditions over timescales from several hundred picoseconds to one nanosecond. Based on the dispersion relation of stimulated Brillouin scattering driven by two laser beams, we obtain a laser frequency difference range within which CBET occurs. In the nonlinear regime, high harmonic of ion acoustic wave (IAW) leads to the reduction of saturation level at high laser intensities ($I\gtrsim 10^{15}\,\mathrm{W/cm^2}$). The wave breaking of harmonic IAW causes the second growth and final saturation of CBET. At low intensities, the linear saturation level slowly varies over time. Compared to Gaussian beams, smoothed lasers with speckles can mitigate CBET saturation level by reducing the effective overlap region. The maximum energy transfer is found at a frequency difference slightly smaller than the linear matching condition due to the reduction of IAW frequency induced by ion trapping. We find that the nonlinear behavior is sensitive to laser intensity, frequency difference, electron density, and ion temperature. The total energy transfer rate increases approximately linearly with laser intensity, underscoring its critical role in CBET control.