| Popis: |
We have observed in superfluid {sup 3}He-{ital B} two-phonon absorption, which is one of the nonlinear effects recently predicted by McKenzie and Sauls. The {ital J}=2{sup +} real squashing mode was excited with two coincident sound pulses at the temperature {ital T}{sup +}, f{sub signal}+{ital f}{sub pump}={ital f}{sub rsq}({ital T}{sup +}), under 0, 2.7, and 3.5 bars pressure. The heights of the attenuation peaks scale almost linearly with the energy of the higher-intensity wave, in qualitative agreement with the theory. Furthermore, a satellite peak appears even in zero magnetic field, which originates from the reflected wave. |
