德拜介质中的布里渊前体
Brillouin precursors in Debye media
摘要：
我们从理论上研究了德拜介质中布里渊前体的形成。我们指出，前体是可见的，只有在传播距离，使介质的脉冲响应基本上是由其吸收的频率依赖性，实际上是高斯。通过简单的卷积，我们得到了参考入射波产生的透射波的显式解析表达式，通过对整个信号的长时间行为的简单检查来区分前兆和主信号。这些表达式与在射频域中对水进行的数值或真实实验中获得的信号非常一致，并特别解释了一些观察到的前体形状。结果得到其他显着的入射波。此外，我们显示相当普遍的布里渊前体的形状单独出现在足够大的传播距离和法律，使其振幅作为这个距离的函数不依赖于精确的形式的入射波，但仅在其积分性质。还检查了介质的静态电导率的发病率，并在弱和强电导率的限制下再次给出明确的分析结果。
英文摘要：
We theoretically study the formation of Brillouin precursors in Debye media. We point out that the precursors are visible only at propagation distances such that the impulse response of the medium is essentially determined by the frequency dependence of its absorption and is practically Gaussian. By simple convolution, we then obtain explicit analytical expressions of the transmitted waves generated by reference incident waves, distinguishing precursor and main signal by a simple examination of the long-time behavior of the overall signal. These expressions are in good agreement with the signals obtained in numerical or real experiments performed on water in the radio-frequency domain and explain in particular some observed shapes of the precursor. Results are obtained for other remarkable incident waves. In addition, we show quite generally that the shape of the Brillouin precursor appearing alone at sufficiently large propagation distance and the law giving its amplitude as a function of this distance do not depend on the precise form of the incident wave but only on its integral properties. The incidence of a static conductivity of the medium is also examined and explicit analytical results are again given in the limit of weak and strong conductivities.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
