I got a sequence of shots of the F-35B as it was taking off for its display at Seafair.  I was a long way down the runway from it so the image quality is not all I would like but what caught my eye was the effect of the afterburner plume on the runway surface.  From shot to shot, there was either this red glow or nothing.  I was wondering whether it was a function of material on the runway like rubber that was burning in the efflux of the engine.  Interesting effect, whatever the reason.