Wave acoustics for propagation of ultrasound along a vortex array in superfluid He-3
Abstract
A wave-acoustics theory was developed to describe the propagation of zero sound parallel to vortex lines in rotating He-3. It is shown that diffraction 'shadow' is formed in which the wave amplitude is suppressed by interference around vortices. The phenomenon contributes to the experimentally observed effect of rotation on the sound amplitude and exceeds the attenuation at large core radii. The dependence of the diffraction contribution on the angular velocity changes drastically at the transition from vortices with a finite core to coreless vortices when the magnetic field is decreased to zero. Conditions for the applicability of the classical geometrical acoustic method in describing zero sound propagation in a vortex array are derived.
- Publication:
-
Unknown
- Pub Date:
- April 1991
- Bibcode:
- 1991wapu.rept.....S
- Keywords:
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- Acoustic Attenuation;
- Acoustic Propagation;
- Helium Isotopes;
- Rotating Fluids;
- Sound Propagation;
- Superfluidity;
- Ultrasonic Radiation;
- Vortices;
- Angular Velocity;
- Magnetic Fields;
- Wave Diffraction;
- Zero Sound;
- Acoustics