How does the white color inside/below a rainbow arise? Inside the rainbow all the colors of the rainbow are joint together to form white light. But how are all these different color cones formed? 
We see only the outside bands of the rainbow colors but the inner parts are joint together to form white light within/below the rainbow, how is that possible?
Are perhaps all the different 'colorwaves' scattered on the tiny waterdrops and giving it a total white color which is coming into our eyes from all directions? And it is not blue, as you could think because of the dominants of blue by N2 and O2, but white because the droplets underneath the rainbow are, just the way they make the clouds white, scattered on H2O??
Is this right or is there another explanation? 
As you can see it is not bright white but still more white compared to the right side of the rainbow....

 A: "...how are all these different color cones formed?"
Say a ray of light hits a raindrop with and angle of incidence of A. The refraction angle is B=arcsin(sin(A)/n). The actual values aren't important yet; only that n>1, so we know that B<A, and the amount of deflection is the positive angle A-B.
The light that enters the drop (yes, some will reflect without entering) will reach the back of the drop. The angle of incidence there will be this same angle B. The deflection angle of the portion that reflects will be 180-2B, and the portion that exits the drop will be A-B, both in the same direction as the original deflection. And this repeats every time the remaining light hits the surface.
As a result, light that exits the drop after one internal reflection deflects a total of 180+2A-4B. But since you are looking 180 degrees away from the original ray already, it is easier to use 4B-2A. Here's a plot:
The brightness of each color, at any particular deflection angle, is inversely proportional to the slope of these curves. Which is zero at the maxima shown. Think about it. :) At lower angles, each color has about the same brightness, and so appears white:

