Quasioptical treatment of electromagnetic Gaussian beams in inhomogeneous and anisotropic plasmas
Quasioptical treatment of electromagnetic Gaussian beams in inhomogeneous and anisotropic plasmas
复制标题
非均匀和各向异性等离子体中电磁高斯束的准光学处理
DOI：
10.1063/1.860782
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
A. Orefice
中科院分区：
文献类型：
--
作者：
S. Nowak;A. Orefice
电磁束高斯行为的主要影响在于焦点区域中的束腰形成，普通几何光学在此处会崩溃。高斯光束的特征，无论是当它们与传输线的组件相互作用时，还是当它们通过非均匀和各向异性介质传播时（例如，在感兴趣的磁活性等离子体的诊断或加热实验中发生的情况），对于许多技术和科学目的都至关重要。本文致力于分析高斯光束的传播，特别表明，正确制定的程函方程包含正确的光线追踪程序所需的所有元素，基本上相当于光束衍射的一阶描述。提出了简单的方法，易于在数值上跟踪光束演化，以适应折射介质和波发射条件的相当普遍的选择。给出了高斯光束在真空、各向同性和各向异性介质中传播的数值结果，并与光学情况下的相应结果进行了比较（证明存在显着偏差）。
The main effect of the Gaussian behavior of an electromagnetic beam consists in a waist formation in focal regions, where the ordinary geometric optics would collapse. The characteristic features of Gaussian beams, both when they interact with the components of transmission lines and when they propagate through inhomogeneous and anisotropic media (as happens, for instance, in the case of diagnostic or heating experiments in magnetoactive plasmas of fusion interest), are of crucial relevance for many technical and scientific purposes. The present paper is devoted to the analysis of the propagation of Gaussian beams, showing in particular that a properly formulated eikonal equation contains all the elements required by a correct ray tracing procedure, basically amounting to a first‐order description of the beam diffraction. Simple methods are proposed, apt to follow numerically the beam evolution for a quite general choice of refractive media and of wave launching conditions. Numerical results are presented for Gaussian beam propagation in vacuum, in isotropic and anisotropic media, and compared (evidencing significant deviations) to the corresponding ones in the optical case.