de Rosny J, Tourin A, Fink M
Laboratoire Ondes et Acoustique, ESPCI, Université Paris VII, UMR 7587, 10 rue Vauquelin, 75005 Paris, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2001 Dec;64(6 Pt 2):066604. doi: 10.1103/PhysRevE.64.066604. Epub 2001 Nov 13.
We report an experimental evidence of the role played by the source on the coherent backscattering effect (CBE) for elastic waves. The experiment is carried out in a chaotic cavity consisting of a silicon plate whose shape is a quarter stadium. With a monopolar source, it has already been shown that the time-integrated squared amplitude at the point source is twice as large as at the other points around the source. Here, by using a dipolar source, we show that we instead obtain two peaks with the same axis as the dipole one's. The shape of this "bicone" is well explained with a modal theory assuming that the source may be modeled by two sources with opposite phases. Then, the theory is generalized to any multipolar emitter and/or receiver. Particularly, we study CBE when emitter and receiver are reciprocal.
我们报告了关于源在弹性波的相干背散射效应（CBE）中所起作用的实验证据。实验在一个由形状为四分之一体育场形的硅板构成的混沌腔中进行。使用单极源时，已经表明点源处的时间积分平方振幅是源周围其他点的两倍。在此，通过使用偶极源，我们表明反而会得到与偶极子轴相同的两个峰值。假设源可以由两个相位相反的源建模，用模态理论能很好地解释这种“双锥”的形状。然后，该理论被推广到任何多极发射器和/或接收器。特别地，我们研究发射器和接收器互易时的CBE。
