Actionscript :: Redraw Hundreds Of Particles In Flash?

I am just starting to learn flash/actionscript 3 and decided to code up a simple particle simulator.The very initial design simply involves filling the screen with a buncha particles which scatter away from the cursor if you were to click.This works, but is a bit unresponsive. I am using graphics.drawCircle() to draw the particles, and each particle is inherited from Sprite.

Listener for mouseclick event:

private function mouseClick(e:MouseEvent):void
{
trace("click");
var now:Date = new Date();
trace("Before: "+now.getTime());

[code]....

How should I make this more efficient? I plan on doing collision detection and other physics interactions later, and this is already a bit slow even without the hefty number crunching code I intend to add later.