| This is a snapshot of some phase slips seen in this lab. The plot shows the peak amplitude of the oscillation of the membrane (which is directly proportional to the velocity in the aperture). In this particular case, phase slips are occurring at a rate of of approximately once per second. One can see that the slips have roughly the same size. The fact that the slips don't all occur at exactly the same critical amplitude is due to the stochastic (random) nature of this phase slip process Ideally, we would like the stochastic spread of the critical amplitude to be small in comparison to the slip size. |
| These phase slips are considered noisy simply because the slip size is quite a bit smaller than the stochastic width. This means that the critical velocity (or critical amplitude) is not very stable and it would be difficult to distinguish true rotations from noise. Note: the "high frequency noise" on the curve is not a problem as this can easily be averaged away without changing any of the features of the sharp drops (phase slips). |
Updated October 25, 1999
Send comments or questions to: Niels Bruckner