  The over-damped motion of a Brownian particle in an asymmetric, bistable,
fluctuating potential shows noise induced stability: For intermediate
fluctuation rates the mean occupancy of minima with an energy above the
absolute minimum is enhanced. The model works as a detector for potential
fluctuations being not too fast and not too slow. This effect occurs due to the
different time scales in the problem. We present a detailed analysis of this
effect using the exact solution of the Fokker-Planck equation for a simple
model. Further we show that for not too fast fluctuations the system can be
well described by effective rate equations. The results of the rate equations
agree quantitatively with the exact results.
