Glowing sun look - Do you know how?

My brain hurts when I try think about how to do this - sort of like an ice cream brain freeze - Any suggestions would help. Is it multiple rings changing or one ring? Too new to know.

It is actually a circle with a gradient fill applied. The gradient has several steps to make it looks like many rings. To animate it i believe it was just a keyframe with the first gradient fill, then another keyframe with a different gradient applied, and then a shape tween. Does this make sense?

Im a little soft on the gradient fill

i cant see the swf