Wave Interactions with Random Inhomogeneous Media

许多天然和人造介质在空间和时间上随机变化，因此在这些随机介质中传播的电磁波、光波和声波在空间和时间上经历随机波动。例如，海浪的微波、光学和声波散射、大气湍流、太阳风、雨、雾、雪、地形、植被、生物介质、复合和无序材料以及粗糙表面。波与随机介质之间的这些相互作用影响到广泛的实际问题，例如这些介质的通信、识别和遥感、逆散射以及介质中物体的成像。近20年来，我们对随机介质中的波进行了广泛的基础研究，并在这一领域取得了实质性的贡献。根据我们的背景和经验，我们建议对多次散射进行广泛的理论研究、数值研究和控制的实验室实验。我们的目标是理解这些多重散射现象的物理过程，并开发出对实际应用有用的数学模型。我们建议的工作将集中在几个具体的主题上，包括散射体和粗糙表面的后向散射增强，粒子和粗糙表面的脉冲散射，横向和距离分辨率，散射波的去极化和偏振度，散射波的高阶矩，致密球形和非球形粒子的矢量辐射传输，随机介质中目标的成像，以及神经网络技术在反散射问题中的应用。我们建议进行严格控制的光学、毫米波和声学实验，以指导理论的发展。我们还建议进行广泛的蒙特卡罗数值模拟，以帮助构建理论模型。这种理论、数值和实验研究的结合在我们的研究中被证明是最有效的。这些研究包括基础研究和实际应用，并应导致改进或新的统计波动理论，这将在例如大气光学、海洋声学、地球物理遥感、雷达、激光雷达、超声波成像、组织中的光扩散、随机介质的逆散射以及无序和复合材料。

Many natural and man-made media vary randomly in space and time, and therefore electromagnetic, optical, and acoustic waves propagating in these random media experience random fluctuations in space and time. Examples are microwave, optical, and acoustic wave scattering by ocean waves, atmospheric turbulence, solar wind, rain, fog, snow, terrain, vegetation, biological media, composite and disordered materials, and rough surfaces. These interactions between the wave and the random media affect a broad range of practical problems such as communications, identifications and remote sensing of these media, inverse scattering, and imaging of objects in the medium. For almost 20 years, we have been conducting extensive basic research on waves in random media, and we have been successful in making substantial contributions in this field. On the basis of our background and experience, we propose to conduct extensive theoretical investigations, numerical studies, and controlled laboratory experiments on multiple scattering. Our objectives are the understanding of the physical processes of these multiple scattering phenomena and the development of mathematical models useful for practical applications. Our proposed work will be centered on several specific topics including the backscattering enhancement from scatterers and rough surfaces, pulse scattering in particles and rough surfaces, lateral and range resolutions, depolarization and degree of polarization of scattered waves, higher order moments of the scattered wave, vector radiative transfer for dense spherical and nonspherical particles, imaging of objects in random media, and application of neural network technique to inverse scattering problems. We propose to conduct carefully controlled optical, millimeter wave, and acoustic experiments in order to guide the development of the theories. We also propose to conduct extensive numerical Monte Carlo simulations to help construct theoretical models. This combination of theoretical, numerical, and experimental studies has proved to be most effective in our research. These studies encompass fundamental research as well as practical applications and should lead to improved or new statistical wave theories which will be useful in applications such as atmospheric optics, ocean acoustics, geophysical remote-sensing, radars,lidars, ultrasound imaging, optical diffusion in tissues, inverse scattering of random media, and disordered and composite materials.