Histogram: colour coded is the logarithm of the probability for the occurrence of a wavelength at a radius normalised at each radius by the sum of all wavelengths for the specific radius. The black lines are proportional to the radius to the power of 2.5 and the lines are a factor of 2 apart from each other. The dashed line has linear slope. One can see that the instability jumps successively between different modes for the wavelength with corresponding jumps in frequency at the same radius.