Currently Being ModeratedOct 10, 2012 7:08 PM (in response to andynick)
2 Shapes: the circle and the wave shape.
For the Wave shape:
[I used another circle shape, went to the Shape > Geometry tab and unchecked closed; I deleted the extra point to make a half-circle, then added midpoints between the center and ends -- then deleted the ends -- makes a nice quarter circle.]
Outline with White; Airbrush; and widen the paint stroke through the middle.
Create an Emitter.
Emission Angle 0
Emission Range 0
Add Behaviors > Particles > Scale Over Life
Adjust the birth and death rates
I drew the size nearest the circle and set the birth rate to 100% and the death rate to 850%
Set the Birth Rate to .... 2
Life to 1.4
Speed to 0
Speed randomness to 0
Color Mode: Over Live
turn down the disclosure triangle on the gradient and for the top (opacity) add a Black swatch at the end (the fade out...)
Set the color swatch to the color of choice and pull off the other tab (you only need the one color throughout the range)
Adjust Birth Rates, Life, Speed , etc. to taste.
Rotate the Emitter or its Group > Properties > Z angle about 30 degrees.
Center the emitter over the center of the circle (dot)