Parametric self-enhancement of the spontaneous decay of sound in superfluid helium.
Parametric self-enhancement of the spontaneous decay of sound in superfluid helium.
复制标题
超流氦中声音自发衰变的参数自增强。
DOI：
10.1103/physrevlett.54.1810
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发表时间：
1985
影响因子：
8.6
通讯作者：
Putterman
中科院分区：
文献类型：
--
作者：
Foster;Putterman
参量放大可显着增强相干单色声音的自发衰减。我们首次在 85 mK 的超流氦中使用 3.25 GHz 声音观察到这种效应。从 10 W/m/sup 2/ 的典型强度开始，声束在仅 1 毫米的传播距离内就被消耗了 99.9% 以上。此外，与朗道-鲁默过程相反，我们观察到指数衰减系数与初始强度的平方根成正比。
The spontaneous decay of coherent monochromatic sound is dramatically self-enhanced by parametric amplification. We observed this effect for the first time with 3.25-GHz sound in superfluid helium at 85 mK. Starting with a typical intensity of 10 W/m/sup 2/ the sound beam is depleted by more than 99.9% over just 1 mm of propagation distance. In addition we observed, in contrast to Landau-Rumer processes, an exponential decay coefficient proportional to the square root of the initial intensity.