I’m not sure how easy that would be, as the most dense areas need to be colored differently, but in particleIllusion the most dense areas usually go white.
You could probably get the general motion you want in particleIllusion, but then you’d need to use After Effects or some comparable application to add a color filter to the output, based on luminance or something.
I don’t know if this is possible in AE or how exactly you’d do it, but it seems feasible.
Alan.
http://www.wondertouch.com