The Blackett Laboratory, Imperial College London, London SW7 2BZ, United Kingdom.
Phys Rev Lett. 2010 Aug 27;105(9):095003. doi: 10.1103/PhysRevLett.105.095003. Epub 2010 Aug 26.
We report the first experimental observation of a long-wavelength hosing modulation of a high-intensity laser pulse. Side-view images of the scattered optical radiation at the fundamental wavelength of the laser reveal a transverse oscillation of the laser pulse during its propagation through underdense plasma. The wavelength of the oscillation λ(hosing) depends on the background plasma density n(e) and scales as λ(hosing)∼n(e)(-3/2). Comparisons with an analytical model and two-dimensional particle-in-cell simulations reveal that this laser hosing can be induced by a spatiotemporal asymmetry of the intensity distribution in the laser focus which can be caused by a misalignment of the parabolic focusing mirror or of the diffraction gratings in the pulse compressor.
我们首次实验观察到高强度激光脉冲的长波长引导调制。在激光的基频散射光的侧视图中，在激光穿过低密度等离子体时，激光脉冲会发生横向振荡。振荡的波长 λ(hosing) 取决于背景等离子体密度 n(e)，并按 λ(hosing)∼n(e)(-3/2)的规律变化。与分析模型和二维粒子模拟的对比表明，这种激光引导可以通过激光焦点中强度分布的时空不对称性引起，这种不对称性可能是由于抛物面聚焦镜或脉冲压缩器中的衍射光栅的不对准引起的。
